Introducing the new RAM Tough-Ball™. Why call it tough? Because this latest addition to the RAM product line has steel inside and out. The seamless transition between RAM versatility and steel durability allows for a multitude of real world, and out of this world, applications. With so many of the things we use incorporating threads and fasteners, there really is no limit to the number of uses you'll find for the RAM Tough-Ball™. The RAP-379U-311837 consists of a 1.5" diameter rubber ball, connected to a 5/16"-18 X .375" male threaded post.