The RAM-B-339-A-237U consists of 2.54cm (1") ball base with 2,54 cm (1")/10,16 cm (4") -20 male camera thread, short double socket arm and 6.35cm (2.5") diameter round base with triple magnetic base adapter. The male thread matches most standard camera and camcorder female threads found on the bottom of the camera. The magnetic base adapter contains 3 rare earth magnets that hold firm to ferrous metals. Simply put this product near the mounting surface and feel it almost jump out of your hand. The composite adapter designed to conceal the magnets is made of durable composite to prevent scratching the mounting surface. Ideally suited for many applications, you're sure to find many ways to use your new magnetic mount at work, home, on the go, or at play.