Compared with the ordinary Extender, the telecentric Extender structure does not generate large angle extended beam, which can better to control of vignetting and edge aberration. It is not easy to significantly change the magnification even increase the rear working distance (within reasonable distance).
One mirror for two purposes
It can be connected to eyepiece and planetary camera, which you can use for visual observation, or planetary camera/SLR.
Picture is only for reference.
Brand: SKY ROVER 2x Extender Optical structure: 4 elements 2 groups
Interface: 1.25 inches Filter thread: M28x0.6
Adapter thread: M42x0.75 Accessories: 2xExtender, cleaning cloth
(1) 1.25 inches interface (2) Locking screw (3) M42x0.75 thread (4) M28x0.6 filter thread