This is a Spike's Tactical Lower Parts Kit known as the Enhanced, model SLPK301.
If you're looking for the highest quality and most durable Lower Parts Kit on the market with all of the upgrades" look no further. The Spike's Tactical Enhanced LPK was designed for the end user who demands the most longevity possible out of the parts in their rifles. Proudly made in the USA.
Features:
Billet Tool-less Trigger Guard
Black Ergo Grip
Black KNS Anti Rotation Gen 2 Mod 2
Ambi Safety
Battle Trigger Group