CVLIFE Red Dot Riser Mount for RMR / RMS / RMSC Footprint Cut, Reflex Sight Optic Riser Plate for Picatinny Rail, 21MM / 23MM / 25MM [ For RMR / RMS / RMSC Red Dot & Picatinny Rail ] - This red dot riser is designed for direct mounting of red dot sight for RMR onto Picatinny mounting platforms,and for red dot with 17mm/0.67in high lens with most iron sights; [ Three Height & Co-Witness Choices ] - For red dot with 17mm/0.67" high lens with most iron sights, 21MM (21mm/0.83" riser) for absolute co-witness; 23MM (23mm/0.91" riser) for medium profile; 25MM (25mm/0.98" riser) for lower 1/3 co-witness; NOTE: Please check your iron sight and red dot lens heights for actual reference when choosing riser height, For example, for red dot len's height ≥ 20mm/0.79inch, 23mm riser is recommended for lower 1/3 co-witness instead of 25mm one; [ Material & Finish ] - Crafted with precision CNC machining from 6061 aircraft-grade aluminum alloy and coated in a matte black anodized finish, this riser mount for RMR red dot boasts anti-corrosion, waterproof, shockproof, sturdy, and robust qualities. It is designed to thrive in even the harshest conditions; [ Detailed Design ] - Significant diagonal lightening cuts reduce excess weight while enhancing impact resistance; The rounded and beveled edges of this reflex sight riser mount are designed to minimize posibility of snagging on your gear or clothes; We've utilized stronger screws with a blue coating, ensuring a firmer red dot mount and preventing loosening under significant impact; [ Note for Installation ] - Securely tighten locking screws again if the red dot wiggles on picatinny rail; Attach 1 pcs of 5mm riser plate at most if slight height adjustment is needed.