Equalizer Visual Vacuum Plunger Cups 2 Today, you witness an increasing number of technicians using vacuum cups to install windshields compared to just a few years ago. Despite common skepticism among technicians regarding vacuum cups, you can trust these ones. The Equalizer Windshield Setting Cups boast impressive features: each cup has a diameter of 7 inches and is capable of lifting up to 90 pounds. Their handles, constructed from cast aluminum, are firmly attached to the cup with high tensile strength bolts. While all these features are commendable, what sets them apart is the highly visible pump vacuum ring. As you pump the plunger to create a vacuum seal, the red line disappears, indicating successful pressure. Conversely, it warns you of pressure loss when it reappears. Unlike many other vacuums, these are specifically designed for curved glass, recognizing the distinction between flat glass and curved glass vacuums.