Hammers 2X40MR Phantom RedDot Sight Phantom Multi-Reticle Reflex Sight, Anodized Matte Black Instantly switchable multi-reticle Reflex sight Two color (green and Red) Illumination for the best contrast setup against the target Screw-on 2x Adapter lens Integral Picatinny mount with large knurled thumb screw 38mm center height perfect for Use on flat tops