The new Starizona EvoFF field flattener turns the Skywatcher Evoguide 50 into a sharp, portable, wide-field imaging scope. The new v2 of the EvoFF has a 55mm backfocus and is now compatible with DSLRs as well as popular astronomical CMOS and CCD cameras. The EvoFF is compatible with cameras having APS (28mm) or smaller sensors. It produces sharp star images over a 6.4-degree field of view! 
The above image compares the native Evoguide field to the corrected field using the EvoFF flattener with an APS format camera EvoFF Backfocus Diagram 
In the Box
Field Flattener
Manual & Warranty
Starizona 1-Year Warranty
EvoFFv2 Instructions