Just plastic bagsI was expecting the liners to be thicker; they are very fine. I will probably not reorder.These liners worked great. No worries when you take them out to tie them! Would purchase them again.While I like the sturdiness of the material as far as leaks or breakage, sealing it up is like any other garbage bag, pull the strings and a gap remains at the top. Press out the air to tie the stings around it and experience wishing you never had a nose. Doesn’t fit all portable commodes. Wish there was an industry standard for that because it can be good multiple situations like in a dry cabin or boat situation in a pinch. But daily waste from caring for an adult is status quo.these were cheaper & thicker than the other brand. these dont leak. other brand didGreat experience and awesome product.Makes clean up fast & easierBest to buy in large (90 or 100) volume.On outside of bag- a printed notice could be applied if cost isn’t too much of a factor.Caution: Human wasteNo complaints, I only wish they came with pads.