This six inch long dowel has great text and illustrations. It reads: 3-shot plug for 12 and 16 ga. Ithaca Repeater to conform with 3-shot federal migratory bird law To install plug: remove barrel; unscrew and remove magazine cap; remove magazine spring; place whole plug inside spring by pushing it between coils a few inches from end of spring; be sure magazine cup is in magazine; then replace spring and magazine cap. Illustration shows plug installed Ithaca Gun Co., Inc Ithaca, N.Y.". This will look great with an old gun. Free shipping.