Check the listing for details. iBOLT Composite 2.5" Single Socket Arm with Circular AMPs Pattern Drill Base. Color: Black, Condition: New. Listed at 13.95 USD. HEAVY DUTY- The iBOLT Single Socket arm is made out of a strong composite material and works with all industry standard 1 inch / 25mm / B Size ball adapters.COMPATIBILITY: Commonly used with IBBZ-33921 or IBBZ-33791 and the iBOLT Bizmount series or DynaMount Series mounts. Compatible with any other Industry standard 1-inch / 25mm / B Size Ball joints and “Octo”/ Octagon pattern adapters and arms.LENGTH of this arm is 2 inches measuring from one end of the arm to the other and 2.5 inches with the base attached.ATTACH 1 inch ball adapters, such as VESA 75/100 / 2T / 4 Prong / AMPS Pattern / Device Holders / 1 inch ball mount bases / etc.FEATURES: industry standard AMPS Pattern adapter. The AMPS pattern consists of four holes located in a rectangular pattern spaced at 30.17mm x 38.05mm (measured as the center-to-center distance between holes). Simply drill this mount onto any flat surface for a secure hold.