Dynaplug Plugs for Bicycle Tire Punctures, 4-Loaded Insert Tubes DESCRIPTION: Package of 4 Dynaplug Micro Pro REPAIR PLUGS loaded and ready for attachment to the tool. STORE: The Tool capsule has machined slots for several of these loaded tubes so you're ready to make a fast repair by having extra tubes on hand. MATERIAL: Tubes are made of Stainless Steel. A Repair Plug is constructed from viscoelastic rubber impregnated cord and non-abrasive brass tip. The plugs are specially designed to be inserted directly into a puncture; if there's a puncture object in the tire, always remove it first. A repair plug can last the life of your tire. MADE IN USA: Dynaplug is a US based company located in Chico, CA.