RAM Mounts 1 Ball Base The Ram-B-349U features a M10 x 1.25 threaded post, while the Ram-B-349-1U is equipped with a M10 x 1.5 post. Additionally, the Ram-B-236U comes with a 3/8-16 pitch male thread attached to a 1 rubber ball. Material: Powder Coated Marine Grade Aluminum Ball Size: 1 Rubber Ball B Size Note: Select the appropriate thread pitch according to the size of the mounting hole in which you intend to install the Ram Ball.