Manufacturer Description The RAP-B-200-2U consists of a double 1" diameter open ball socket with two 360° rotation points and a center swivel joint that rotates forward and back 180°. This arm is compatible with other RAM 1" B-Ball components. Dimensions: Overall Length: 6.25" Socket-To-Socket Length: 5" Material: High Strength Composite Ball Size: 1" "B" Size