6.5" size fits most revolvers with up to a 3-inch barrel and small frame semi-auto handguns ** 8.5-inch size fits most revolvers with up to a 4-inch barrel ** The 9" holster fits medium frame semi-auto handguns with up to a 5-inch barrel ** The 12-inch holster fits revolvers with up to a 6.5" barrel, and Ruger 22 semi-auto handguns with up to a 6.5" barrel.