Wet back tester also called rewet tester is designed to determine the rewet properties of nonwoven topsheets or coverstocks of hygienic and sanitary materials.

 

A piece of coverstock is placed over a standard absorbent medium(10 piles of filter paper) which is then loaded three times according to the repeated STT method proposed in ISO 9073-13 with a specific quantity of simulated urine.

 

After the third dose, a simulated baby weight(SBW) is placed onto the coverstock and absorbent medium to ensure even spreading of the liquid.

​

A pre-weighted pick up paper is then placed on the coverstock and the simulated baby weight(SBW) is again put on top. The mass of liquid absorbed by the pick up paper is called as wetback.