The mirror used to deflect light to guiding camera has 10 × 7 mm area (mirror dimensions are 10 × 10 mm, but the mirror is angled at 45 degrees). This is enough for guiding cameras with very large 2/3" format detectors without any significant vignetting.
The Moravian off axis guider for G2 series is equipped with standard M42 × 0.75 (T-thread) on the telescope side. Adding this OAG to a G2 camera with external filter wheel the optical thickness becomes 55 mm. This means G2 camera with OAG can be used on numerous optical systems, including Newtonian coma-correctors, refractor field flatteners etc.