RAM® MOUNTFINGER-GRIP™ UNIVERSAL MOUNTSUCTION CUP BASE DOUBLE BALL MOUNTING SYSTEM•Material: Power Coated Marine Grade Aluminum•Ball Size: B•Kit includes the Finger-Grip™ Universal Phone & Radio Holder holds Most Cell Phones 2-Way Radios & More (RAM-HOL-UN4U) a Twist-Lock™ Suction Cup Base with Ball (RAM-B-224-1U) & a Medium-Sized Double Socket Arm (RAM-B-201U)