The 2 "edge focusor eliminates the disadvantages of optical systems that reveal the sharpness of the image at the ends of the field of view when shooting astro. The corrector is provided for 2" eyepiece extents. On the other hand, it ends with a T2 (M42x0.75) thread and a T2 / Canon ring that allows the Canon EOS camera body to be mounted (for other DSLRs a dedicated T-ring is needed). Dedicated to Explore Scientific ED APO. Also works with apochromats and Meade LX90 and LX200 ACF tubes.