91270 - M4 - Mesa Tactical Ambi-Hook Loop for Magazine Extension The housing is then black

The housing is then black anodized to provide you with a lfetime of durability

Weight 1 oz Dimensions 4 × 2 × 2 in Color Tactical Black No Logo

and a hardness of C36 on the Rockwell scale

There is a difference

ATTENTION M1/M2 FOREND SHOPPERS - THIS IS TERRIBLY IMPORTANT:  Some M2 forends make use of "locking nubs" on the receiver-end of the forend to lock it into place

91270 - M4 - Mesa Tactical Ambi-Hook Loop for Magazine Extension The housing is then black91270 Mesa Tactical Ambi Hook Loop for Magazine Extension The Urbino Tactical stock system features a molded pocket at the front where the stock meets the shotgun receiver. A nylon blank is provided to fill this pocket, but it can also accept any of several stamped steel sling loops, hook loops, or push button sling swivel mounts. This ambi style sling attachment features mounts on both side of the receiver, and is coated in a tough mil spec manganese