The RAP-B-121BBU connects to RAP-B-121U mounts; it is used as an extra ball to mount an additional device to your current mount.
Material:
Powder Coated Marine Grade Aluminum
Ball Size:
1" Rubber Ball "B" Size
Note:
The "U" in the part number reflects product packaged in poly bag.
B size 1" (Holds up to 2 lbs)
Powder Coated Marine Grade Aluminum
Adapter
Packaged in Poly Bag