Designed for use with all M-LOK compatible Hand Guards and Forends, M-LOK Polymer Rail Sections provide a cost effective method of attaching various 1913 Picatinny spec rail-mounted accessories such as lights, vertical grips, etc. Injection molded from a proprietary reinforced composite for enhanced strength and durability while remaining lightweight. Rail Sections also feature beveled ends to reduce snagging and eliminate sharp corners and edges. All hardware necessary for attachment directly to M-LOK Slots on either aluminum or polymer hand guards and forends is included. Mfg: Magpul SPECS: MAG593 - 11 Slots, max overall length of 4.9" MAG592 - 9 Slots, max overall length of 4.1", MAG591 - 7 Slots, max overall length of 3.3" MAG589 - 3 Slots, max overall length of 1.6".