Ram Mounts Go Pro Action Camera Mounting Kit Round Base The Rap-B-138-Gop1 Consists Of A 2.5" Diameter Round Base With The Universal Amps Hole Pattern, Standard Size Double Socket Arm And 1" Diameter Ball With Custom Gopro® hero Adapter. The Mount Is Designed With A Ram 1" Diameter Patented Rubber Ball And Socket System That Has Adjustment Points At Both Ends Of The Double Socket Arm; This Allowing For Almost Infinite Adjustment And Perfect Viewing Angles. The Ram-B-138-Gop1 Can Be Used As A Drill-Down Or A Temporary, Removable Mounting Solution With The Addition Of The Rap-339u Accessory. The Gopro® hero Adapter Attaches Directly To The Under-Side Of The Camera, Replacing The Factory Mounting Bracket. Specifications Material:High Strength CompositeBall Size:B Size 1" Rubber Ball Compatible Devices Gopro Hero Gopro Session Garmin Virb Sjcam Sj4000 Sjcam Sj5000x Elite 4k Muvi Veho K-Series K-2 Pro 4k Xcel 1080c Vivitar Hd