Connor Trailer Lock - 3/4" Brass Coupler Lock 1615160 FITS MOST COMMON COUPLERS  Fits most trigger-latch-style couplers (1/4" pin) DEPENDABLE STRENGTH  Engineered to increase durability and strength SECURE YOUR COUPLER  3/4" usable length- Includes 2 keys EASE OF USE  Insert the key and turn left to unscrew the lock. Secure the lock into the coupler hole and then turn right to tighten the lock CONSTRUCTED FROM HEAVY DUTY SOLID STEEL FOR SUPERIOR STRENGTH  Durable Brass Finish - For replacement keys please visit our website or contact us on Amazon