These are black plastic cord locks that fit on the parachute cord that we sell.

Size is approximately 7/8" tall (22 mm), 11/16" wide (17.5 mm) wide. Eye Diameter is 3/16" (4.75 mm)

It might be hard to get larger cord through the eye of the cord lock, so we recommend using a short length from a plastic drinking straw that is split up the middle