These are 4-40 Safety Lock Kwik-Link Clevis' from Dubro.Used to connect to a servo horn.
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 SPECS: Length: 1-1/8" (approx 28.5mm)Width: 5/16" (approx 8mm)
NOTE: Servo in pictures not included!