A stabilizing brace, also known as a pistol brace or an arm brace, is an accessory for some modern firearms. It is a replacement for the buttstock, and is primarily designed to help the shooter fire their weapon one-handed.
The brace is fitted with adjustable straps in order to tighten it around the shooter's forearm, helping increase accuracy and reduce recoil during single-handed firing. Short-barreled firearms equipped with braces are legally considered pistols.
Stabilizing braces can alternatively be used as traditional stocks. In 2015, the ATF ruled that shouldering the brace of a weapon with a barrel length of less than 16 inches constituted a "redesign" of the gun into an SBR. This has later changed in 2017, when the ATF reissued a letter stating that firing a brace-equipped weapon from the shoulder doesn't make it an NFA firearm anymore.