This trainer clips up to 3 different rows and then zips up giving u may can help different levels of compression as ur waist gets slimmer this is an aggressive trainer that may can help offers a tighter compression. Material is latex on the outside and inside is cotton, seamless under clothing. IN BETWEEN SIZES PLEASE GO ONE SIZE UP. BEFORE ZIPPING UP PLEASE MAKE SURE TO PULL THE ZIPPER CLOSE TOGETHER.