The ERGO SuperLite Modular Free Float M-LOK Rail System is designed to create a clean and sleek profile. Ventilation cutouts aid in rapid cooling and provide substantial weight reduction. – 7 Version Weighs 6.9 ounces – The ERGO SuperLite Modular M-LOK Rail System M-LOK slots are located at the 3 6 and 9 o’clock positions allowing users to run with or without rail covers (4332-4PK). – Specifications: – 100% Made in the USA. 6061-T6 construction – Steel Barrel Nut included – Type III Hard-coat black anodized finish – Lightweight one piece free float design – M-LOK design accepts Ergo and all other M-LOK compatible accessories – Full length seamless Mil-Spec 1913 Picatinny top rail – Scalloped Picatinny rail slots for comfort and style – Sleek 1.8 outside and a 1.37 inside diameter – For AR-15/M16 platforms (Not AR-10 SR25 etc.) – Made to Magpul M-LOK specifications