M LOK rail sections, QD mounts and Picatinny rails make up just a few of our M-LOK Midwest Industries Ultra Lightweight Series Handguard 12 inch - M-LOK. The revolutionary M-LOK rail system has been widely described as being the next big thing. Shop our selection of rails at cheap prices today! Equip your AR with a 12 inch M-LOK Rail Handguard, for secure, modular attachment of tactical accessories! Available in Black or Flat Dark Earth. Lifetime.