Here is some interesting info comparing the different typse: http://www.slowtwitch.com/Products/T...ants_2765.html I personally don't believe in sealants. The first line of defense against a flat is the tire and thus the most important; the last line is the tube and thus the least important; in the middle is tire liners, a good tire liner like the Panaracer Flat Away is the best liner on the market and light in weight at 32 grams, I actually tried to get a tack to penetrate the liner and it broke the tack, then I tried a finishing nail I banged through a piece of wood to support it and bent the nail trying to penetrate the liner, neither penetrated that liner.