Originally Posted by wellhouse
i believe it is 'special' to zodiac and is a form of pvc they call Sharc duotex but check with your dealer.
SHARC is a varnished polyurethane. There will be a blue logo on the tube somewhere that says "SHARC" if they are that material.
If not, then they're PVC.
SHARC requires light sanding, before wiping with MEK and gluing with plastomer adhesive. PVC, skip the sanding.