Check the listing for details. 6Pack Empty Chamber Key Chains with Flags for Safety Tags Gun Pistol Indicator. Color: Multicolor, Condition: New. Listed at 17.38 USD. Clear Handgun Rack with Anti-slip Strip Acrylic Gun Display Stand Pistol Holders. ▪ Used to clearly signal your firearm chamber as empty to others when not in use. ▪ Chamber flag for use with most common rifle and pistol calibers including 9mm. 45 ACP, 22lr. 223, 5.56, and. 308.