Which trailer coupler lock fits a 2-5/16 inch or rolled-lip coupler?

Answered by RV Parts Giant · Upland, CA · October 31, 2026

Short answer: Match your ball size first, then your coupler style: the Rhino USA kit is 2-5/16 inch only and excludes rolled-lip and underslung couplers, while the Kohree kit excludes irregular, square and adjustable ones. Of the locks we stock, only the TowSmart 732 listing says it also secures the latch while towing.

This is what our listings state for each lock.

Lock	Ball sizes	Fit limits on the listing	Lock type
Rhino USA kit	2-5/16 in	A-frame, 50x50, 50x60. Max lip width 4-3/8 in, max lip height 5/16 in. Not rolled-lip or underslung	Coupler lock + latch pin lock, keyed alike
Kohree kit	2 in, 2-5/16 in	Not irregular, square or adjustable couplers	Solid steel, 4 keys, weather plugs
Kohree heavy-duty	1-7/8 in, 2-5/16 in	None listed. No 2 in	Structural steel, about 7.7 lb
Kohree keyless	2-5/16 in	None listed	Hardened steel, combination
bROK Universal	1-7/8, 2, 2-5/16 in	"Most stamped couplers"	Fills the ball socket, swivel head
bROK Lock Warrior HD	1-7/8, 2, 2-5/16 in	None listed	Hardened 3/4 in shackle
Master Lock 389DAT	1-7/8, 2, 2-5/16 in	None listed	Pick- and pry-resistant
TowSmart 7277	"Most couplers"	Multiple positions	Bright red shackle, about 2.65 lb
TowSmart 732	1-7/8, 2, 2-5/16 in	Several positions	Solid brass

Three steps to choosing

Read the ball size stamped on your coupler. Don't guess it from a hitch ball you own.
Identify the style. Rolled lip, underslung, square and adjustable couplers are the styles that come up as exclusions. Check the limit lines above for yours.
Measure the lip if you are looking at the Rhino. It is the only listing with dimensions: 4-3/8 in maximum width and 5/16 in maximum height. Anything bigger won't fit.

Rolled-lip and underslung couplers

The Rhino kit rules them out, and none of the other listings confirms that it fits them. So we can't promise a fit from the listing alone. The bROK Universal has adjustable positions for different coupler designs, but its listing is written around stamped couplers. Send us a photo of your coupler before you order.

Parked or towing?

Most of these locks stop someone from hitching up a parked trailer. The bROK Universal fills the ball socket, so it can't go on while the coupler is on a ball. The TowSmart 732 is the only listing that says it secures the latch while towing as well. For the Rhino kit, the latch pin lock is sold as part of the parked-trailer theft kit, and the listing does not mention towing, so don't assume it.

The lock also has to live outside in the weather. Look at the Kohree kit's weather plugs, or the plating and powder coat on the bROK locks, if yours will sit in storage for months.