The RAP-B-379U-371637 consists of a 1″ diameter rubber ball, connected to a 3/8″-16 X .375″ male threaded post.
U.S. Standard Thread Diameter and Pitch Option:
3/8″-16 X .375″
High Strength Composite & Steel
1″ Rubber Ball “B” Size
The “U” in the part number reflects product packaged in poly bag.