Q Honey Badger Rail Kit, M-LOK, 12, Fits Honey Badger/AR Upper Receivers, Clear Anodized Finish, Gray, Includes Barrel Nut and Hardware 12-HB-MLOK-HG-KIT The Honey Badger Handguard is compatible with all M4 upper receivers" comes in a 12" M-LOK configuration. Comes with the Barrel Nut and Hardware.