Essentially though it is heavy duty 2 layer plastic sheet. Rather then rolling clay out directly you roll out between sheet. Also by placing your teflon worksheet in between attached layers of plastic sheets you create a system where you can instantly cover clay while you do something else.
For example if you are using a stencil.
1. Roll out clay on teflon worksheet in between Clay Saver Sheets
2. Flip top layer back and cut out pieces with stencil.
3. Remove the excess clay from stencil cut out. Here's the saving part. While your returning clay to storage simply flip top layer of plastic sheet back over your clay work piece to keep from drying. By doing this you add working to perform other tasks without risking your clay drying out.
This is one example of many but once you begin to work this way you will never go back.
This video indirectly demonstrates the how to setup clay saver sheet.