Midwest Rake 18 x 2 Ribbed Aluminum Roller Replacement Sleeve, 1-1/2 ID Ribbed rollers are used to evenly distribute resin and other bonding materials when installing fiberglass and other high performance fabric and mesh laminate reinforcement systems. The use of these rollers enhances the fiberglass/fabric saturation and containment, while removing air bubbles and pockets. Also good for concrete overlays to gauge thickness.