This is a Hogue Rubber known as the Stock, model 22010.
Hogue's Ruger 10/22 Long Rifle Action Rubber Overmolded Stock is one of the finest replacement stocks on the market today. Made for the Ruger 10/22 chambered in .22 long rifle with a barrel diameter of .920" (Bull Barrel)" it is constructed from a lightweight reinforced polymer then covered in Hogue's popular Overmolded rubber exterior providing excellent control and comfort. This lightweight drop in replacement stock features two sling swivel studs and a soft recoil pad.
Features:
Fits Ruger 10/22 Chambered in .22 Long Rifle with a barrel diameter of .920 (Bull Barrel);Front and Rear Sling Swivel Studs;Length of Pull: 13.75