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: Twelve 4-40 Safety Lock Kwik-Link Clevis'
REQUIRES: 4-40 Pushrods of modeler's choice
Installing clevis' onto pushrods
SPECS: Length: 1-1/8"
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)