The Sky-Watcher Field Flattener is a superb quality, non-focal reducing field flattener optimised for DSLR imaging on refractor telescopes with focal ratios of between f/5.
5 to f6.
0.
Will also provide much improved results on refractors with focal lengths narrowly outside this optimised f/range.
Integral T-Ring adaptor thread.
High quality CNC machined body with gloss black anodised finish.