Trailer Tongue Locks
Our top picks
Best 2-5/16 in
Proven Industries Model 2516
Custom fit wraps the coupler, little room for tools.
About $250 (provenlocks.com list)
Check price at Proven ↗Best 2 in
Proven Industries Model 2178
Custom fit for 2 in couplers.
Check current price
Check price at Proven ↗Best universal
Trimax UMAX100
Hardened steel with nylon housing.
About $130 (trimaxlocks.com list)
Check price at Trimax ↗Quick answer: A trailer tongue lock is another name for a coupler lock: it locks onto the coupler at the end of the trailer tongue so it cannot be hitched. For 2-5/16 in tongues, Proven Model 2516 is the high-security pick; Trimax UMAX100 and Master Lock 379ATPY are universal options that also fit 2 in and 1-7/8 in.
Comparison
| Lock | Best for | Fits | Price (approx.) | |
|---|---|---|---|---|
| Proven Industries Model 2516 | Best 2-5/16 in | Most 2-5/16 in trigger- and thumb-latch couplers | About $250 (provenlocks.com list) | Check price ↗ |
| Proven Industries Model 2178 | Best 2 in | Most 2 in couplers | Check current price | Check price ↗ |
| Trimax UMAX100 | Best universal | Most 1-7/8 in, 2 in and 2-5/16 in couplers | About $130 (trimaxlocks.com list) | Check price ↗ |
| Master Lock 379ATPY | Best budget | 1-7/8 in, 2 in and most 2-5/16 in couplers | About $36 (masterlock.com list) | Check price ↗ |
| Blaylock TL-34 EZ Lock | Best push-button | 2-5/16 in trigger-style couplers (Atwood, Fulton, Shelby, Titan, Demco and similar) | Check current price | Check price ↗ |
How we chose: picks are based on published specifications, materials, fit charts, manufacturer information and patterns in owner reports. We have not lab-tested these locks. Prices are approximate list prices seen on maker sites in October 2026 and change often.
Our picks in detail
Best 2-5/16 in
Proven Industries Model 2516
Who it is for: Owners of valuable 2-5/16 in trailers stored unattended.
Pros
- Custom fit wraps the coupler, little room for tools
- 1/4 in steel, tubular key
- Keyed-alike option across the range
- Can capture most safety chain hooks
Cons
- Expensive
- Must match your exact coupler model
- Heavy
- Type: Coupler lock (custom-fit)
- Fits: Most 2-5/16 in trigger- and thumb-latch couplers
- Build: 1/4 in steel, black powder coat, puck lock, 7-pin tubular key
- Keyed alike: Yes (keyed-alike option across Proven line)
- Price: About $250 (provenlocks.com list)
Can secure most 5/16 in safety chain hooks per maker; check the fit index for your coupler.
Check price at Proven ↗Best 2 in
Proven Industries Model 2178
Who it is for: Boat and utility trailers with 2 in couplers wanting top security.
Pros
- Custom fit for 2 in couplers
- 1/4 in steel
- Keyed-alike option
Cons
- Price not confirmed on our check
- Fit is coupler-specific
- Type: Coupler lock (custom-fit)
- Fits: Most 2 in couplers
- Build: 1/4 in steel, black powder coat, puck lock
- Keyed alike: Yes (keyed-alike option)
- Price: Check current price
2 in version of Proven's coupler lock (spec per dealer listing at nctrailers.com).
Check price at Proven ↗Best universal
Trimax UMAX100
Who it is for: Owners wanting more security than budget locks without custom-fit prices.
Pros
- Hardened steel with nylon housing
- Fits 1-7/8, 2 and 2-5/16 in
- Keys alike with other Trimax locks
Cons
- Universal fit, not glove-tight
- Bulkier than budget locks
- Type: Universal coupler lock
- Fits: Most 1-7/8 in, 2 in and 2-5/16 in couplers
- Build: Solid hardened steel, ballistic nylon housing, 9/16 in shackle
- Keyed alike: Keys alike to other Trimax locks (per catalog)
- Price: About $130 (trimaxlocks.com list)
Best budget
Master Lock 379ATPY
Who it is for: Budget buyers and people with several trailers.
Pros
- Low price
- Fits 1-7/8, 2 and most 2-5/16 in couplers
- Rekeyable commercial version
Cons
- Looser universal fit
- Lighter than custom steel locks
- Type: Universal coupler lock
- Fits: 1-7/8 in, 2 in and most 2-5/16 in couplers
- Build: Rust- and corrosion-resistant body, keyed different, rekeyable commercial version
- Keyed alike: Can be ordered keyed-alike commercially; retail is keyed different
- Price: About $36 (masterlock.com list)
Limited lifetime warranty.
Check price at Master Lock ↗Best push-button
Blaylock TL-34 EZ Lock
Who it is for: Owners of 2-5/16 in trigger-style couplers.
Pros
- Push-button, no padlock needed
- Cast aluminum, made in USA
Cons
- 2-5/16 in trigger couplers only
- Price not confirmed on our check
- Type: Push-button coupler lock
- Fits: 2-5/16 in trigger-style couplers (Atwood, Fulton, Shelby, Titan, Demco and similar)
- Build: Cast aircraft-grade aluminum, hardened steel pin, made in USA
- Keyed alike: -
- Price: Check current price
TL-36 and TL-38 cover other sizes.
Check price at Blaylock ↗
Tongue lock vs ball lock vs hitch lock
- Tongue/coupler lock: covers the coupler; protects an unhitched trailer.
- Ball lock: a type of coupler lock that plugs the socket. See ball locks.
- Hitch lock: locks the receiver pin on your vehicle. See hitch locks.
How to choose
- Ball size: read the size stamped on your coupler (1-7/8 in, 2 in or 2-5/16 in). Custom-fit locks are sold per size; universal locks cover all three but fit looser.
- Coupler type: trigger latch, thumb latch, lever/latch style (Atwood-type), surge-brake (common on boat trailers) or cast-steel. Custom-fit makers publish fit charts; check yours before buying.
- Material and coverage: thick steel that wraps the whole coupler leaves less room for pry bars and cutters than a small ball plug with an exposed shackle.
- Lock cylinder: tubular and disc cylinders resist picking better than basic wafer locks. Look for a keyway cover so dirt and road salt stay out.
- Keyed alike: if you also lock the hitch pin, spare tire or doors, a keyed-alike set means one key for everything.
- Weather: powder coat, stainless pins and sealed keyholes matter if the trailer sits outside or near salt water.
Our pick
Proven Industries Model 2516: best 2-5/16 in. Owners of valuable 2-5/16 in trailers stored unattended. If budget matters more, see the other picks above.
Check price at Proven ↗FAQs
- Is a tongue lock the same as a coupler lock?
- Yes, in everyday use.
- Do I need a 2-5/16 in tongue lock?
- Only if your coupler is 2-5/16 in; check the stamp.