OPF-S, ACRO (Optics Platform, Staccato, ACRO) is designed for optics ready Staccato P, C, C2, XL and XC with the factory or aftermarket 0.285 front sight, it is compatible with Aimpoint P1/P2, and Steiner MPS. Do not use any of the cheap Chinese copies or sights with the ACRO footprint, we do not guarantee it will fit them. OPF-S, ACRO features a dovetail compatible with the steel rear sight we designed and make for OPF-S, RMR and OPF-S, ACRO.