Oatey PVC Shower Pan Liner is an economical, flexible liner designed for use in tile showers and other concealed waterproofing applications. It's made of 40 mil thick, flexible PVC sheet and marked in 6 in. increments for easy of measuring. The kit includes 2 Oatey PVC Dam Corners -- preformed, flexible corners designed to seal the junction of the curb and door jamb where a flexible liner membrane has been used to build a tile shower installation. They have a universal design for right or left corner installations and are made of 40 mil PVC. Oatey products have earned the trust of plumbing professionals for over 100 years.