The Ergo Grip SuperLite Modular Free Float M-LOK Rail System provides a 1.8eee outside diameter and a 1.5eee inside diameter designed to create a clean and sleek profile. Ventilation cutouts aid in rapid cooling, and provide substantial weight reduction. M-LOK slots are located at the 3, 6, and 9 oeeeclock positions allowing users to run with or without rail covers. The M-LOK rail provides multiple attachment locations for Ergo M-LOK accessories including Ergo WedgeLok slot covers and as a host to all other M-LOK compatible products. Installation is simple using a standard eeeee drive 1 3/16eee crow foot wrench (not included), and all necessary mounting hardware is included.