$9
Keymod rail is used with handguards and plates. The major advantage over RIS – you can individually select the place of installation for each rail. In case if the operator needs only a few mounts (Weaver rails) at top and bottom guard he can use only minimal 60 mm length rails – it will save weight and provide more comfortable grip. There are few options of rail lengths, but 3 length options are most typical. Mounting seats are made as keyholes and retaining nut firmly enters the slot and torqued by the bolt from outside.
Option 2
Option 3