Vixen Tube Rings and accessory mount rings clamp onto telescope tubes to provide mounting points for accessories and mount heads. They are designated by their inside diameter. Both types can be joined by dovetail tube plates on the bottom for attachment to Porta, GP-Series and SPHINX mounts.
Tube Rings are sold in pairs and have 1/4"-20 threaded tripod holes on the top and bottom. The optional Tube Ring Accessory Plate (#AM-AD-3548, B&H code "VITRAP") fits across the top of the rings for additional mounting options and greater stability.
Accessory Mount Rings are sold singly and have a 1/4"-20 threaded hole on bottom and 1/4"-20 tripod screw on top.