Fantastic plastic forward grip - Tdi Arms 5-Position Folding Grips w/ Battery Compartment

It's a good deal for a little under $25. It's chunky and solid, but also chunky and clunky. The adjustment button is a little sticky, and also sharp on one side. I bet that smooths out with use, and at least the spring inside is strong. The rail clamp is a little cheaty, and I'm not happy with that part. The base is split down one side, and the tightening bolt just "squeezes" the to halves together, so they pinch on whatever rail you put it on. It's not a uniform tension all the way down the base, just on one end, so I'm skeptical.

The battery compartment is plenty spacious, enough to hold two AA's side by side, and doesn't take much effort to get open.