Front sight irises will fit Sinclair, RPA, Anschutz, Diana, Steyr, and other front sights. All front sight irises have calibrations laser cut and have a black matte non-reflective finish internally and externally. Available in 18mm or 22mm. Horizontal crossbar with an adjustable inner ring. Adjustment range: 2.4mm - 4.4mm.
Sinclair, Issue:3B, Page:213