This is an original Civil War M1855 socket bayonet issued to fit the US Percussion Model 1855 Springfield, as well as the M1861 and M1863 rifled-muskets. This was also designed to for use with various U S manufactured 58 caliber muskets. Blade surfaces are very fine with a smooth attractive mix of steel gray patina. “S” inspectors mark present . Blade measures 17-7/8″, fuller measures 16-1/8″, overall length 20-7/8″, socket length 3″, muzzle ring internal diameter is 0.8971″.