This is a Midwest Industries Handguard, model MI-HK91M.
Midwest Industries is a proven leader in the firearm industry. Made in America" focusing on the small details to make your rifle platform better. The addition of their HK M-Lok handguard will give you modularity you want to add lights and tape switches to this old school rifle platform. This model features 37 full and 7 half M-LOK slots and one five slot M-LOK compatible rail is included. There are also four anti-rotation QD swivel sockets. Fits HK 91 and clones.
Features:
Slim 1.6 diameter for a great feel;Constructed of 6061 aluminum hard coat anodized
100% Made in the U.S.A.
Mil-spec top rail