Kowa TSN-AR42GT 42mm Standard T2 Fit Adapter Ring with Protection Glass T-mount This is also the extension

This is also the extension bar for the CEM40/60/70 GEM45 mounts

and coin shooting

You don't necessarily need a Glasspathcorrector for Schmidt-Cassegrains with f/10

Baffles have been added to increase contrast and AR coatings are optimized for the 656nm wavelength

AUX Operation temperature -10°C ~ +40°C Pier/Tripod Optional pier Warranty Two year limited OTA size and length dependent

Kowa TSN-AR42GT 42mm Standard T2 Fit Adapter Ring with Protection Glass T-mount This is also the extensionAdapter Ring to Combine the TSN DA10 or TSN DA20 Digiscoping Adapters With T2 Rings Integrated Protective Glass Prevents the Camera Sensor From Becoming Dirty