This is a Magpul Industries Trigger Guard known as the MOE, model MAG417-GRY.
The MOE Trigger Guard (Magpul Original Equipment) is an enhanced polymer drop in replacement for the AR15/M4 weapons platform. It features a shallow "V" shape for better use of gloves in tactical shooting or cold weather operations. The MOE Trigger Guard is non-folding" has rounded edges" and fills the annoying "gap" at the rear of the standard trigger guard. Also works well with most 7.62x51 AR platforms but some custom fitting may be required. All mounting hardware included. Made in U.S.A.
Features:
Enhanced polymer drop in replacement
For the AR15/M4 weapons platform
All mounting hardware shape for better use of gloves