I used the odd looking rubber plug with a hole in the middle used for the screwdriver like tool to insert into the tire and cut off the excess with provided cutter, then a CO2 cartridge. I used two cartridges as it took two for me to learn how to do it, swore I'd never do that again as if I did not get it the second time, I'd be SOL. Rear tire. Limped home 50 miles under 55mph. I now use a BMW kit and the slime compressor, but want one of those crew in plug type kits I saw demonstrated at a COG rally. I'm thinking the "fix-a-flat" folks are using liability lawyer words concerning using their product on bikes, I've used it as a temporary fix for a leaking tire from around the bead, not a flat. BTW, took off the rear tire, patched it from the inside and put another 5000 miles on it, small hole in between treads. I know, I know heresy for some here, but I was comfortable with it.