- +All-metal zinc-alloy trumpets with chrome plating at a price where rivals ship ABS
- +12V heavy-duty electric air solenoid included in the box
- +Three trumpets pre-assembled on one solid bracket — single-point mounting
- +Factory-rated 5 dB louder than United Pacific's standard 46129 at a similar or lower street price
- +Street price runs well under list at multiple established truck-parts retailers
- −No test distance published for the 150 dB rating, and the ±10 dB tolerance is unusually wide
- −Chord frequencies (Hz) not disclosed by the manufacturer
- −Horn-only kit — compressor, air tank, air line, and pressure switch all sold separately
- −6-month warranty is short next to the 1-2 years offered by Kleinn and HornBlasters
- −Retailer spec data is inconsistent — one major parts listing shows 145 dB for the same part number
- −Very few independent sound recordings of this exact model exist online
Methodology
This review aggregates publicly available information from manufacturer specifications, retailer listings, and verified user reviews. We do not perform hands-on testing. Last reviewed: July 14, 2026. Specifications below were cross-checked across United Pacific’s syndicated factory spec sheet as it appears on Amazon, FinditParts, Vehicle Safety Supply, Lund Truck Parts, and Peterbilt Parts, plus owner commentary from Train Horn Forums. Where retailers disagree on a number, we say so.
Quick verdict
The United Pacific 46151 Competition Series is the louder, heavier-built sibling of the company’s long-running 46129 chrome triple, factory-rated at 150 dB (±10 dB) versus the standard horn’s 145 dB. For roughly $130-$155 street you get three chrome-plated zinc-alloy trumpets pre-mounted on a single solid bracket, with a 12V heavy-duty electric air solenoid already in the box — a genuinely complete horn assembly for trucks that already carry onboard air. We rate it 3.7/5: the all-metal construction and bundled solenoid are real value at this price, but the undisclosed test distance, missing frequency data, and short 6-month warranty keep it out of the top tier.
What it is
The 46151 is a three-trumpet, air-operated train horn sold under United Pacific’s “Competition Series” banner — the step-up line above the brand’s standard chrome triples. United Pacific Industries is a California-based manufacturer best known for restoration and dress-up parts for semi trucks and classic vehicles, and this horn is squarely aimed at that audience: owner-operators and chrome-shop customers who want a loud, polished roof- or frame-mount horn cluster for a working rig.
Unlike the complete kits sold by HornBlasters or Kleinn, this is a horn-only product. The three zinc-alloy trumpets arrive chrome-plated and pre-assembled on one solid mounting bracket, with a 12V electric air solenoid plumbed into the base — you supply the compressed air. The whole assembly measures roughly 15-1/2” long by 11-3/4” wide by 11-1/2” tall, per the factory spec sheet, and ships with a mounting pad and hardware. Package weight is listed at about 15.6 lb, which tells you these are not thin-wall decorative trumpets.
Who it’s for: anyone with an existing air source — a semi’s brake air system (check your local regs before tapping it), or an aftermarket compressor-and-tank setup on a pickup — who wants maximum chrome and volume per dollar. Who it’s not for: buyers starting from zero who need a compressor, tank, and plumbing in one box.
Specifications
| Spec | Value |
|---|---|
| Model | United Pacific 46151, Competition Series |
| Sound output | 150 dB ±10 dB, manufacturer rating (test distance not disclosed) |
| Air pressure | 150 PSI maximum (operating pressure not published) |
| Trumpets | 3, mounted on a single solid bracket |
| Material | Zinc alloy, chrome plated |
| Valve | 12V heavy-duty electric air solenoid (included) |
| Dimensions | ~15-1/2” L × 11-3/4” W × 11-1/2” H |
| Package weight | ~15.6 lb |
| Chord frequencies | Not disclosed |
| Included | Horn assembly, solenoid, mounting pad, mounting hardware |
| Warranty | 6 months |
| Street price | ~$131-$151 (list $197-$224 depending on retailer) |
Two honesty notes on that table. First, United Pacific publishes the 150 dB figure with a ±10 dB tolerance and no test distance — a swing that spans the difference between an ordinary air horn and a genuinely painful one. Our guide to advertised vs real-world decibels explains why distance-free ratings should be treated as marketing ceilings, not measurements. Second, the spec data isn’t perfectly consistent across the retail channel: FinditParts lists this same part number at 145 dB ±10 dB, matching the standard 46129’s rating, while Amazon, Vehicle Safety Supply, and Lund Truck Parts all carry the 150 dB figure from United Pacific’s sheet. We report the manufacturer number but flag the disagreement.
What’s in the box
- Three chrome-plated zinc-alloy trumpets, pre-assembled on a solid single bracket
- 12V heavy-duty electric air solenoid, pre-plumbed
- Mounting pad
- Mounting bolts and hardware
Not included — and this matters for budgeting: no compressor, no air tank, no air line, no pressure switch, no relay, no horn button. If you’re building from scratch, budget for a small onboard-air system before this horn makes a sound. Our air tank size guide and compressor buying guide cover what to pair with it.
Pros
- All-metal construction at a plastic-horn price. Chrome-plated zinc-alloy trumpets in the $130-$155 bracket, where several competitors substitute ABS bells.
- Solenoid included. The 12V heavy-duty electric valve is in the box — a part that many bare-horn listings quietly omit.
- One-bracket install. All three trumpets arrive aligned on a single solid bracket with a mounting pad, so there’s no multi-horn positioning or re-plumbing puzzle.
- Louder factory rating than the standard model. United Pacific rates the Competition Series at 150 dB versus 145 dB for its own 46129 — and at the retailers that stock both, the 46151’s street price was actually the same or slightly lower.
- Wide retail availability. Stocked by Amazon, Peterbilt Parts, FinditParts, and multiple independent truck-parts houses, so price-shopping and returns are straightforward.
Cons
- No test distance on the dB rating. 150 dB ±10 dB with no measurement distance is the loosest kind of loudness claim; treat it as a ceiling.
- No frequency data. United Pacific doesn’t publish the trumpet pitches, so you can’t compare its chord to a Nathan or Leslie on paper.
- Horn only. Every other component of a working system — air supply, plumbing, switching — is extra.
- Short warranty. Six months, versus one to two years on comparable Kleinn and HornBlasters hardware.
- Inconsistent channel data. At least one major parts retailer lists the 46151 at 145 dB, muddying the Competition Series’ main selling point.
- Thin independent evidence. Forum users note there are almost no recordings of this exact model online, so tone and real-world volume are hard to preview.
Alternatives
- Grand General 69991 Heavy Duty Deluxe — the most direct rival: another chrome three-trumpet, solenoid-included horn from a truck-accessory house. Our Grand General 69991 review covers it in depth.
- Vixen Horns VXH3118 — another chrome-plated triple with a 12V electric solenoid, sold for everything from semis to pickups. See our Vixen VXH3118 review.
- United Pacific 46129 — the standard-series version of this same horn, rated 145 dB ±10 dB at the same 150 PSI max. At the retailers we checked, its street price was actually slightly higher than the 46151’s, making the Competition Series the stronger value of the two.
More options across brands live in our United Pacific reviews hub and the single vs dual vs quad trumpet comparison.
Install / compatibility notes
The 46151 needs three things you must supply: compressed air up to 150 PSI, a 12V switched circuit for the solenoid, and a mounting surface that can carry roughly 15 lb of chrome through potholes and wind load.
- Air supply. On a semi, installers commonly tee off the accessory air circuit — never the brake circuit directly — through a pressure protection valve; on a pickup, plan a dedicated compressor and a 2-3 gallon tank. Our PSI guide explains why running near the 150 PSI ceiling matters for output.
- Air line. A triple this size breathes best through 3/8” or 1/2” line; 1/4” line will choke it. See the air line size guide.
- Electrical. The included solenoid is a standard 12V unit — wire it through a relay and fused feed per our relay wiring guide rather than through the factory horn circuit alone.
- Mounting. The solid bracket and pad are drilled for a flat surface: roof, deck plate, or frame rail. Trumpets should face forward or slightly down so the bells drain; our mounting guide covers placement and moisture protection.
One editorial caution: chrome-plated zinc alloy looks great new but is less forgiving of rock chips and road salt than stainless or brass, so under-bumper mounting in snow states will age the finish fast — factor that into placement.
Sources
- United Pacific — 3 Trumpets “Competition Series” Chrome Train Horn (46151) product page — official listing; origin of the factory spec sheet (150 dB ±10 dB, 150 PSI max, dimensions, solenoid, included hardware)
- Amazon — United Pacific 46151 Competition Series 3 Trumpet Train Horn — 150 dB ±10 dB rating, 150 PSI max, heavy-duty solenoid, listing title cross-check
- Amazon — United Pacific 46129 Chrome Plated 3 Trumpet Train Horn — standard model’s 145 dB ±10 dB rating used for the Competition Series comparison
- Vehicle Safety Supply — United Pacific 46151 — $134.25 price, 6-month warranty, package dimensions and 15.6 lb weight, included items
- Vehicle Safety Supply — United Pacific 46129 — $146.84 price for the standard 46129 used in the price comparison
- Lund Truck Parts — United Pacific 46151 — $148.79 price, 6-month warranty, dimensions, solenoid and hardware confirmation
- FinditParts — United Pacific 46151 — $131.49 price vs $224.28 MSRP, zinc-alloy material confirmation, divergent 145 dB listing
- FinditParts — United Pacific 46129 — $145.49 price for the standard 46129 used in the price comparison
- Peterbilt Parts — United Pacific 46151 — $150.28 price vs $197.74 list, shipping weight
- BBB — United Pacific Industries Inc. — Long Beach, California headquarters; parts for big rigs and classic vehicles
- Kleinn — Warranty Information — one-year standard / two-year select-product warranty used in the warranty comparison
- HornBlasters — Warranty Policy — one-year standard warranty (two years on compressors and tanks) used in the warranty comparison
- Amazon — Vixen Horns VXH3118 Triple Trumpet Train Horn — chrome-plated 3-trumpet 12V train horn cited in the alternatives section
- Train Horn Forums — United Pacific 46115 vs 46151 vs Grand General 69991 — user reports: popularity at chrome shops, price positioning, scarcity of recordings
Train Horn Hub aggregates publicly available data. We do not test products in-house. All trademarks belong to their respective owners.
The 46151 is a smart pick for semi and heavy-truck owners who already have onboard air and want a solid-metal chrome triple at a street price under $155. Buyers who need a complete kit, published test-distance numbers, or a longer warranty should look at Kleinn or HornBlasters packages instead.
Frequently asked questions
Quick answers to the questions people ask most about this topic.
- How loud is the United Pacific 46151 really?
- United Pacific rates it at 150 dB ±10 dB with no test distance disclosed, so treat that as a manufacturer ceiling rather than a measured figure. One major parts retailer lists the same part number at 145 dB, and there are few independent recordings to settle it.
- What is the difference between the 46151 and the standard 46129?
- Both are chrome-plated zinc-alloy triples with a 12V solenoid and a 150 PSI maximum. The Competition Series 46151 carries a 150 dB ±10 dB factory rating versus 145 dB ±10 dB for the 46129, and at the retailers that stock both, its street price was the same or slightly lower.
- Does the 46151 come with a compressor and air tank?
- No. It is a horn-only assembly — trumpets, bracket, 12V solenoid, mounting pad, and bolts. You need to supply an air source (a truck's accessory air circuit or an aftermarket compressor and tank), air line, and a switched 12V circuit.
- What PSI does the United Pacific 46151 need?
- The maximum rating is 150 PSI; United Pacific does not publish a minimum operating pressure. Like most triples, it will sound noticeably weaker below roughly 100 PSI, so a system that holds 120-150 PSI gets the most out of it.
- Will the 46151 fit on a pickup truck?
- Physically yes — the single-bracket assembly is about 15-1/2 inches long and mounts to any flat surface that can carry roughly 15 lb. But pickups need a dedicated onboard-air system added, since the horn ships without a compressor or tank.
