OPF-VP9, ACRO is only guaranteed to work with Aimpoint ACRO P1 and P2, and Steiner's MPS. We have not tested it with the cheap Chicom sights under different guises from various companies that also use the ACRO footprint. We neither endorse, nor support their use on OPF-VP9, ACRO.
Designed for HK VP9 and Aimpoint's ACRO P1 and P2, OPF-VP9, ACRO is precision machined from 4140 steel and black nitride coated.
VP9 Tactical's taller suppressor height sights provide lower 1/3 co-witness with OPF-VP9, ACRO and P1/P2, but the front tritium/dot is partially obscured at the bottom.
Steiner's MPS has a larger window size, the front tritium is fully visible through the MPS sight window.
We will soon stop including the L keys with all OPF products, L keys will become optional, we strongly suggest a proper torque wrench to impart the correct torque value.