These are Model 3 design universal sheath/holster clips. They are excellent for mounting on KYDEX and leather carry systems and are very durable. This model is Black coated (Tactical style) and is common on military and SWAT sheaths/holsters. These have a c-style locking design.
Specifications:
Universal Sheath/Holster Clip
Black (Tactical) Finish
(2.10 x 1.25 x 0.25) inches