The BATFE has reversed course on the popular Sig Brace. These braces have been growing in popularity with shooters across the country. The current issue of American Handgunner even ran a piece about it. If you are using it to shoulder mount an AR Pistol, its time to stop or face a charge of having an unregistered Short Barreled Rifle or SBR. Use them only as they were intended. All letters that came with the brace are now void.