The shaft of the Mushroom Style plug expands under pressure to fill the puncture. The mushroom head of the plug seats on the inner wall allowing no air to escape. This insures maximum reliability from its' revolutionary design. For use with: Mini Plug: Tubeless Tire Puncture Repair Kit, Tubeless Tire Puncture Repair Kit: Gun Kit Product Contents: Replacement Mushroom Plugs Caution Make sure tire is filled with air and is not completely flat before cutting the extra plug While cutting extra portion of plug stem above the tire, make sure that you have left 1-2 mm, this will help in better sealing