The CRL Wood's Powr-Grip® 6" (152 mm) Concave Vacuum Cup have a rugged steel bail that provides an attachment point for securing loads. Attaches to either flat or curved surfaces including automobiles, boats, or recreational vehicles, and can be moved quickly from one place to another without damaging surfaces. The Red-Line indicator warns user of any vacuum loss, and a check valve allows re-pumping without loss of remaining vacuum. Lift tabs on pad edges permit instant release. Each cup is supplied with a vacuum pad protector.