CRL proudly offers you the unique line of Wood's Powr-Grip® Vacuum Cups. These specially designed, hand actuated cups operate on a pump system, and create a vacuum under their gripping pad section. As well as non-porous flat surfaces, the deep, concave design of the pad make for easy attachment on curved or irregular non-porous surfaces. The pump plunger has a red band to indicate suction level at all times. When it shows less than 100% vacuum left, simply pump the plunger until you reach the original vacuum pressure without removing the cup from the glass! To release, just depress a trigger on the opposite end of the handle from the plunger. There are four models of the basic Wood's Powr-Grip® Vacuum Cup. All come with a vacuum-molded carrying case to protect the cup when not in use.