Panaracer makes a great tire liner called the FlatAway liner, it's made of kevlar cloth, it's about 5th the weight of a Mr Tuffy and it's tougher than a Mr Tuffy but it's a one tire use liner and it cost more. Depending on the circumstances it may be better to simply buy a more flat resistant tire, tires like the Specialized Armadillo will prevent most flats and even protect against Goatheads (i know because I used them in the Mojave Desert of California). A heavy plastic style liner is just plain nuts, you could easily between the combined weight of a tire plus the plastic liner exceed the weight of a tire like the Armadillo.