The size is the inner diameter of the ring and should match the outer diameter of the telescope tube.
A set of two rings is for sale.
On the upper side with 1/4 "-20 threaded holes.
The lower side has M6 threaded holes for the dovetail guide rail, including mounting bolts and washers.
76mm, 90mm, 101mm, 140mm rings are in black color.
116mm, 142mm, 160mm, 182mm rings are in white color
For 235mm and 288mm rings, since these rings are available in both white and black, please inform us which color do you want, otherwise we will send randomly.
This cast-aluminum tube ring set features quick-release, hinged clamp knobs and felt lining, allows you to securely attach a telescope optical tube to a mount and tripod. The hinges open to allow easy installation of the optical tube and the locks can be loosened during use to allow tube Rotation and balancing.
In order for astrophotography lovers to capture the spectacular views of the sky, one of the two rings in the set has a 1/4"-20 piggyback camera adapter on it, the other has a threaded 1/4"-20 hole. The piggyback camera adapter can be removed for mounting an adapter plate for a guide scope on top of the tube rings.
Pls choose the size that matches the outside diameter of your telescope tube.