The Vixen Direct Wide Adapter provides frame-filling prime focus connections between the Vixen 60mm drawtubes of the R200SS & VC200L telescopes and your SLR camera. It can also be used on other Vixen telescopes with 60mm inner diameter focuser drawtubes (which includes the majority of their refractors) but with those scopes you'll need to lengthen the optical path with the Vixen #2956 extension tube in order to achieve focus.
The Direct Wide Adapter allows easy rotation for image orientation after mounting-you'll never go back to simple T-Ring connections again.
You'll need your camera system's specific Vixen T-mount adapter, but the Direct Wide Photo Adapter doesn't screw in to the female threads on the front of a T-mount. Instead, it uses three set screws to affix to the outside of the T-mount! This keeps the internal opening nice and clear, allowing the best possible pictures and especially eliminating vignetting when using a full-frame 24x36mm format camera combined with a fast optical system in the telscope.