Feature●Clear acrylic. Non-corrosive●Specific gravity: 1.17 - 1.20. Cubic inches per lbs.: 23.7 - 23.1. Water absorption, 24 hours: 0.3 - 0.4%.●Rockwell hardness (M): 80 - 100●Maximum temperature: 140°F - 200°F●Tolerance: +/- .002"Description These solid plastic balls are used in check valves, relief valves, float valves and everything from carburetors to toggle switches and more. They also work well for many manufacturers as light load ball bearings.