These are 4-40 Safety Lock Kwik-Link Clevis' from Dubro. Used on model aircraft for connecting control rods to control surfaces. FEATURES: Self tapping design leaves no slop on the pushrod threads. Square nylon shank for easy installation and adjustment. 10% lighter than a steel clevis. Brass plated stepped steel pin does not bind on control horns and has a large flat head for easy removal. Brass plated steel safety lock slides into a groove on the pin for a secure and solid lock. Safety lock is mounted in a track system on the clevis body to help prevent it from being lost. INCLUDES: Two 4-40 Safety Lock Kwik-Link Clevis' REQUIRES: 4-40 Pushrods of modeler's choice Installing clevis' onto pushrods SPECS: Length: 1-1/8" Width: 5/16" Shank Width: 3/16" COMMENTS: For other sizes of safety lock clevis', use: 2-56 (DUBQ1510 qty 2) (DUBQ1511 qty 12) 4-40 (DUBQ1514 qty 2) (DUBQ1515 qty 12) 2mm (DUBQ1518 qty 2) (DUBQ1519 qty 12) For replacement Slide Locks, order DUBR0821