Kleinn designs its train horn systems in Tucson, Arizona, and its kits are some of the loudest bolt-to-the-frame systems you can buy. Here's what a Kleinn kit really costs and takes to install, and how it compares to a battery train horn that skips the air system entirely.
The Kleinn Lineup at a Glance
Kleinn sells its train horns two ways: horns only, or as complete "HK" kits that bundle the horns with a 12-volt compressor, an air tank, a pressure switch, fittings, and a wiring kit. The horns-only route looks cheap — the Model 220 "Mini Beast" dual horns are $142.95 — but horns alone can't make a sound. Kleinn lists a minimum 1.5-gallon tank for them, so you still need an air source. For a working system, the kits are the honest comparison:
| Kleinn kit | Horns | Rated output | Compressor / tank | Price (Kleinn direct) |
|---|---|---|---|---|
| HK5 "Mini Beast" | Dual ABS (Model 220) | 151.8 dB @ 150 PSI | 6275RC, 50% duty / 1.5 gal | $549.95 |
| HK6 "Sentinel" | Triple chrome ABS (Model 500) | 151.8 dB @ 150 PSI | 6275RC, 50% duty / 1.5 gal | $619.95 |
| HK7 "Beast" | Triple black ABS (Model 230) | 155.1 dB @ 150 PSI | 6350RC, 100% duty / 3 gal | $839.95 |
| HK9-Slimline "Demon" | Triple stainless steel (Model 730) | 157.8 dB | 6450RC, 200 PSI max / 3 gal slim tank | $1,149.95 |
The HK7 is the kit most people shop, and it's a good one. You get three trumpets of 18.5, 16.5, and 14.5 inches on a flat rack that can be split up for tight frames. It comes with a 100% duty-cycle compressor rated at 2.11 CFM and a 3-gallon tank. Kleinn also includes a tire-inflator kit with a 24-foot hose and says the system can air up tires as large as 37 inches. That onboard-air bonus is the real reason to buy a Kleinn kit, and we'll come back to it.
Loudness: 151.8 to 157.8 dB vs the 150 dB Class
Kleinn publishes some of the highest numbers in the aftermarket: 151.8 dB for the HK5 and HK6, 155.1 dB for the HK7, and 157.8 dB for the steel Model 730 in the HK9-Slimline. The spec sheets list those figures "@ 150 PSI," meaning tank pressure, but they don't say how far from the horn the microphone was. That matters. Distance and test method can move a horn rating by several dB, which is why numbers from different brands are rarely apples to apples. We explain how that works in is a 150 dB train horn real?
Our loudest battery horns, the Extreme and Boss Series, are rated in the 150 dB class. In practice, a Kleinn HK7 and a 150 dB battery horn are both far past what any stock vehicle horn does, and both will be heard blocks away. The steel Kleinn Demon horns do carry a real edge on paper. If the biggest possible number is your only goal, a full steel tank system is where that number lives.
What a spec sheet won't show is sustain. A tank kit stores air and spends it. The pressure switch on the HK7 cuts in at 110 PSI and shuts off at 150 PSI. Kleinn's own chart shows the 6350RC needs about 59 seconds to refill a 2.5-gallon tank across that band, and 4 minutes 35 seconds from empty. A long blast sags as tank pressure drops. A battery horn's built-in compressor feeds the trumpets as you hold the button, so there's no tank to drain.
Install: What the Kleinn Manual Actually Asks You to Do
Kleinn's HK7/HK8/HK9 user manual is clear and thorough, and it describes a real project. Here are the main steps:
- Disconnect the vehicle battery's ground cable before you start.
- Mount the compressor and tank on a flat, secure spot as close to the battery as you can. If it ends up under the truck, you must route the remote air-intake filter to a dry location.
- Drill 3/16-inch holes for the leader-hose bracket, and plumb air line from the tank to the horn solenoid.
- Wire a relay so the pressure switch is fed from a switched (ignition-on) 12-volt source. Kleinn's wiring diagram calls for a 30-amp fuse. Use at least 10 AWG positive wire if the compressor is mounted far from the battery, such as in the bed.
- Install a safety valve at the top of the tank and a drain cock at the bottom. Then drain condensation regularly. The manual warns that rusted tanks can fail and should be discarded.
The compressor draws up to 21 amps from your truck's electrical system. LEER, which sells the HK7, puts a typical install at 3 to 5 hours depending on the vehicle. At a 2026 independent-shop labor benchmark of about $140 an hour, paying someone for that comes to roughly $420 to $700 on top of the kit. Kleinn does offer bolt-on systems for specific trucks. Its Universal Spare Tire Location kit mounts in place of the spare with no drilling, but it runs $1,089.95 with the Beast horns and $1,369.95 with the steel Demon horns, and you give up the spare-tire spot.
A battery train horn has none of those steps. There's no wiring into the truck, no relay, no tank to drain, and no air line to route. For more on why that matters long-term, see our battery train horn vs compressor-and-tank kit breakdown.
Real Cost: Full System vs Full System
| Cost item | Kleinn HK7 (tank kit) | Extreme Series battery horn |
|---|---|---|
| Horns + air source | $839.95 complete kit | $365 (sale; list $430), compressor built in |
| Rated output | 155.1 dB @ 150 PSI | 150 dB class |
| Install | 3–5 hours typical; about $420–$700 at shop rates | None, works out of the box |
| Power source | Truck's 12V system, fused relay circuit | Cordless tool battery (sold separately) |
| Wireless remote | Optional Sniper remote, up to 200 ft | Included, 160 ft; 2,000 ft upgrade available |
| Moves between vehicles | No, bolted and wired to one truck | Yes: truck, boat, UTV, tailgate |
Even before labor, the HK7 kit costs more than twice what the battery horn does. The one hidden cost on the battery side is the tool battery, and most people shopping this category already own a few.
Which One Should You Buy?
Buy a Kleinn kit if you want onboard air anyway. A 100% duty compressor and a 3-gallon tank that fill tires, run air bags, or engage lockers are a genuinely useful truck upgrade, and the train horn rides along on top. It's also the right call if you want the highest published dB numbers and you're happy spending a weekend, or a shop bill, on the install. Kleinn's steel Demon horns carry a 2-year warranty and a 157.8 dB rating, which is hard to argue with if money and space aren't the limit.
Buy a battery train horn if you want the horn itself, not an air system. The Extreme Series Train Horn for Milwaukee® 18v Battery is the closest match to a Kleinn HK7. It's a 150 dB-class quad-trumpet horn that runs on any Milwaukee® M18™ battery, includes a 160 ft wireless remote, and costs $365 with nothing to install. Versions are available for DeWalt® 20V MAX™, Ryobi® ONE+™, and other major battery platforms.
If you'd like to trigger it from the cab or across a campsite, the Long-Range Remote (2,000ft) extends control well beyond Kleinn's 200 ft Sniper remote. For a wider look at every tier and battery option, start with our complete train horn buyer's guide.
FAQ
Is a Kleinn train horn louder than a battery train horn?
On paper, yes, by a few dB. Kleinn rates its kits from 151.8 dB up to 157.8 dB, while our Extreme and Boss Series battery horns are rated in the 150 dB class. Because Kleinn doesn't publish the test distance, the gap is hard to pin down. Both are extremely loud, and the battery horn holds full volume on long blasts because it has no tank to drain.
Can I buy just the Kleinn horns and skip the compressor?
You can buy them, but they won't sound without an air source. The Model 220 horns list a minimum 1.5-gallon tank and need 140 to 160 PSI, so you'll still need a compressor, tank, pressure switch, and wiring.
How long does a Kleinn kit take to install?
LEER, a Kleinn retailer, puts a typical HK7 install at 3 to 5 hours depending on the vehicle. The work includes mounting the compressor and tank, drilling for brackets, plumbing air line, and wiring a fused relay to an ignition-switched circuit.
Which Kleinn kit compares best to a 150 dB battery horn?
The HK7 "Beast" is the closest match. It's a triple-trumpet kit rated at 155.1 dB for $839.95. The HK5 and HK6 are cheaper but use a 50% duty compressor and a smaller 1.5-gallon tank.