Brand: Partners Size: 60cm x 90cm Underpads are made up of a soft material which doesn’t irritate the skin and wicks moisture away from the body. Some underpads also have Super absorbent poly beads (SAP) which absorbs the fluid and converts them into gel. Underpads are usually made up of several layers. A soft topmost layer which comes in contact with the body, an absorbent middle layer and a waterproof plastic bottom layer.