Keymod Rubber Neoprene Inserts (10 Pcs) - $8.95 + FS over $35 (Free S/H over $25)

This is a simple, yet really good product. I bought a bunch of extras thinking they'd easily come off, but they stay on well and the extra grip is never a bad thing.

The only downside is that they have cleverly packaged them per 10. Lets just look at a common Keymod handguard like this; Midwest Industries carbine Keymod handguards They have 12 key slots. So your probably going to have to buy more than one pack of these unless your lucky with a B5 Systems, Bravo -10 slotted handguard.