The RAP-B-379U-252825 consists of a 1" diameter rubber ball, connected to a 1/4"-28 X .25" male threaded post. The male thread matches most standard camera and camcorder female threads found on the bottom of the camera.
U.S. Standard Thread Diameter and Pitch Option:
1/4"-28 X .25"
High Strength Composite & Steel
B Size 1" Rubber Ball
The "U" in the part number reflects product packaged in poly bag.