This iris can be changed from crosshair to a crossbeam like the Vario model. It also allows the shooter to change cant angles without any tools. Scaling allows you to reposition exact cant angles by graduations. Ring adjusts from 2.3mm to 4.3mm. Ring thickness remains at 1.6mm. Available for 18mm and 22mm front sights.
Sinclair, Issue:3A, Page:211