Sylvan Arms SA5 Pro Folding Stock Adapter Features The Sylvan Arms SA5 Pro Folding Stock Adapter is CNC-machined in the USA from 4140 steel giving it the strength to hold up under repeated folding and use in the field. This left-hand fold configuration directs the stock off to the side away from the ejection port keeping the action clear during transport or storage. It threads onto most AR15 standard 1-3/16 inch by 16 thread receivers without requiring any additional parts and it works with standard AR15 bolt carrier groups without modification. At just 9.4 ounces the adapter adds minimal weight to the completed rifle. Installation is straightforward requiring no disassembly of the rifle or pistol before mounting and the adapter ships complete with a castle nut wrench and 1045 steel bolt extension for a full ready-to-install package. It is compatible with platforms chambered from .223/5.56 up through .308 Win as well as most 9mm AR builds though it is not compatible with Tippmann 22 or LWRC pistols. Shooters running certain 9mm bolt carriers with standard 5/8 inch sizing can use the included bolt extension after removing the pin and weight from the BCG. This adapter is a durable versatile solution for anyone looking to add genuine folding capability to an existing AR build. Sylvan Arms SA5 Pro Specifications Brand: Sylvan Arms Model: SA5 Pro Compatible Hosts: AR-15 AR9 Material: 4140 Steel Fold Direction: Left Hand Weight: 9.4 oz Color: Black Available At: GrabAGun