The RAM-B-201-A, short double socket arm, has a socket at both ends that accommodates 1" ball bases. This socket technology allows for almost infinite adjustment and perfect viewing angles. Dimensions: Overall Length: 2.38" Socket-To-Socket Length: 2" Material: Powder Coated Marine Grade Aluminium Ball Size: 1" Rubber Ball "B" Size Note: For security purposes a locking knob is available for this arm, part number RAM-KNOB3L