These are 2mm 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 2mm Safety Lock Kwik-Link Clevis'

REQUIRES: 2mm 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
                                                                  kpm 1/26/2001
                                                                          ir/jl