Screw-opening D-ring often used for paracord bracelets.
Dimensions:
Small
Outside Measurements: 1" x 1"
Inside Measurement: Widest part - 1/2", Bar - 3/8"
Medium:
Outside Measurements: 1.25" x 1.25"
Inside Measurement: Widest part - 5/8", Bar - 7/16"