Kleinn HK5 Mini Beast Dual Train Horn Kit Review (2026)

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 June 23, 2026. For the Kleinn HK5 we relied primarily on Kleinn’s official product page for the kit and its component pages — the Model 220 “Mini Beast” horns, the 6275RC waterproof compressor, and the 6275RT 1.5-gallon tank — cross-checked against retailer listings at Summit Racing, CARiD, Amazon, and 4 Wheel Parts. Every number below traces to a source in the list at the end of this review.

Quick verdict

The Kleinn HK5 “Mini Beast” is a complete, sealed dual-horn air kit that packs a genuine locomotive note into one of the smallest footprints Kleinn sells. We rate it 4.0/5. You get Kleinn’s waterproof 6275RC compressor, a 1.5-gallon steel tank, and two individually mounted Model 220 ABS trumpets that the brand rates at 151.8 dB at 150 PSI. The trade-offs are an ABS-and-zinc trumpet build rather than chrome or brass, a small tank that empties quickly under sustained leaning, and a decibel figure Kleinn publishes without a stated test distance.

What it is

The HK5 is a universal, bolt-on dual train horn kit aimed at truck, Jeep, and SUV owners who want a real train-horn chord without the bulk of a triple or quad setup. Rather than a single cast cluster, it uses two separate Model 220 “Mini Beast” horns — a short 11.5-inch trumpet and a longer 16.25-inch trumpet — each with its own solenoid and airline. That modular layout is the whole point of the “Mini Beast” line: you can tuck the two horns into different spots under a bed, behind a bumper, or inside fender wells where a one-piece triple simply won’t fit, and still get a two-note chord.

Because it ships with its own compressor, tank, pressure switch, and plumbing, the HK5 is a self-contained system. It does not piggyback on an existing onboard-air setup, though Kleinn positions the same 6275-series air center for tire inflation and other pneumatic accessories if you add a manifold later. In the Kleinn lineup it sits a rung above the compact HK2 dual and below the triple-horn HK6 and HK7 “Beast” kits.

Specifications

Spec	Value
Model	HK5 — “Mini Beast” Dual ABS Train Horn System
Horns	2 × Model 220 (individually mounted)
Trumpet sizes	11.5” L and 16.25” L
Trumpet material	Composite ABS with zinc alloy base
Sound output	151.8 dB at 150 PSI (test distance not disclosed)
System pressure	110 PSI on / 145 PSI off (Model 2151 switch); 150 PSI max
Compressor	Model 6275RC, oil-less, sealed waterproof, 12V
Compressor output	1.76 CFM; 50% duty cycle at 100 PSI (72°F)
Compressor draw	20 A max
Air tank	Model 6275RT, 1.5-gallon steel, Cortec-coated, 5 × 1/4” NPT ports
Fill time	0–150 PSI in ~3 min 27 sec
Solenoids	2 × Model 307 Vortex, 12V (one per horn)
Airline	1/4” OD to each horn
Power	12V DC
Warranty	1-year limited defect
Price	$549.95 (Kleinn direct)

Loudness claim

151.8 dB @ 150 PSI

Air system

1.76 CFM, 1.5-gal tank

Duty cycle

50% @ 100 PSI

Power

12V, air-tank

What’s in the box

• Two Model 220 “Mini Beast” ABS train horns (11.5” and 16.25”) with individual mounting
• Model 6275RC waterproof 12V air compressor
• Model 6275RT 1.5-gallon steel air tank
• Model 2151 pressure switch (system on/off)
• FIT56 fitting pack — drain valve, safety blow-off valve, outlet fitting
• Two Model 307 Vortex 12V solenoids (one per horn)
• Horn button, thread sealant, 12 ft of 1/4” air tubing, 12 ft of 3/8” airline, mounting hardware

Pros

• Complete sealed system in one box — the 6275RC compressor is marketed as fully waterproof for water crossings, which suits off-road builds
• Modular dual horns (11.5” and 16.25”) mount separately, so they fit tight spaces where a one-piece triple won’t
• Each horn gets its own 307 Vortex solenoid and dedicated 1/4” airline for fast, lag-free response
• Kleinn discloses real engineering data — 1.76 CFM, 50% duty at 100 PSI, fill time, dimensions, and component weights
• Established US brand with a strong dealer network, replacement parts, and downloadable install manuals

Cons

• Composite ABS trumpets with a zinc base — louder than budget plastic, but not the chrome or solid brass of premium horns
• The 1.5-gallon tank is small; sustained or repeated blasts drain it fast and you’ll hear the note sag while the compressor catches up
• The 151.8 dB rating is published with no stated measurement distance, so it isn’t directly comparable to distance-qualified numbers
• Only a 1-year limited defect warranty — short next to the multi-year coverage some rivals offer
• Requires wiring, plumbing, and two mounting locations — this is a real install, not a 10-minute bolt-on

Alternatives

• Kleinn HK2 — Kleinn’s more compact dual ProBlaster with a smaller air system. A better fit if space and budget are tighter and you can live with a slightly thinner note.
• Kleinn HK6 — Steps up to a triple-horn “Beast” chord and a larger air system. The pick if you want a fuller three-note blast and have room to mount it.
• Kleinn HK7 — Another triple “Beast” kit with a bigger compressor and tank for buyers who lean on the horn often and don’t want the note to sag.

For context on how these decibel claims actually translate to loudness, see our decibels explained guide and our roundup of the loudest train horns. You can also browse all of our Kleinn reviews.

Install / compatibility notes

The HK5 is a universal kit, so it fits most trucks, Jeeps, and SUVs with 12V electrical and a spot to mount the tank and two horns. Plan three mounting decisions before you start: where the two trumpets point (rearward or downward, away from the cab, protected from road spray), where the 1.5-gallon tank lives (frame rail or bed), and where the waterproof compressor mounts. Kleinn rates the 6275RC as sealed against moisture and dust, which makes under-vehicle mounting realistic on an off-road rig, but you should still keep electrical connections and the horn button clean and dry.

Wiring follows the standard train-horn pattern: the Model 2151 pressure switch cycles the compressor between roughly 110 and 145 PSI, and the horn button triggers the two 307 Vortex solenoids that dump tank air to the trumpets. Because each horn has its own solenoid and 1/4” airline, both fire together with minimal lag. Budget a few hours for a clean install, and use a relay on the compressor circuit given its 20-amp draw. If you’re new to this, our train horn install guide and relay wiring guide walk through the wiring and plumbing step by step.

One practical note on the small tank: at 1.5 gallons the HK5 is tuned for short, punchy blasts. If your use case is long, sustained leaning — show duty, parades, repeated honks in traffic — the compressor’s 50% duty cycle and modest 1.76 CFM mean recovery, not endless air. For most street and trail use, that’s a fair trade for the compact footprint.

Sources

• Kleinn — Model HK5 Dual Train Horn Kit product page — kit specs (151.8 dB at 150 PSI, horn sizes, PSI range, included items, price, warranty)
• Kleinn — Model 220 “Mini Beast” Dual ABS Train Horns — trumpet material, dual 307 Vortex solenoids, individual mounting
• Kleinn — Model 6275RC Waterproof Air Compressor — 1.76 CFM, 50% duty at 100 PSI, waterproof sealing, 12V/20A
• Kleinn — Model 6275 Medium-Duty 150 PSI Air System — 1.5-gallon steel tank, fill behavior, system architecture
• Summit Racing — Kleinn HK5 ProBlaster Dual Train Horn Kit — retailer cross-check on availability and configuration
• CARiD — Kleinn HK5 Pro Blaster Train Horn Kit — retailer cross-check on price and listing
• Amazon — Kleinn Air Horns HK5 Complete Dual Train Horn System — retailer cross-check
• 4 Wheel Parts — Kleinn HK5 Complete Dual Train Horn Package — retailer cross-check on availability