This 4” x 2” Thermoplastic Rubber-Round Tread wheel has molded thermoplastic rubber treads chemically bonded to an industrial plastic core. They are prominent on equipment in pharmaceutical laboratories, hospitals, food service facilities, schools and many other institutional applications where noise can be an issue and maximum floor protection is appropriate. These wheels are not recommended in industrial settings which involve heavy loads in harsh and abusive environments. Thermoplastic rubber-round treads are non-marking, reticent, vibration resistant, and shock absorbing. They will roll smoothly over small objects, shielding floor surfaces. Like most soft rubber wheels, though not nearly as bad as natural rubber, they tend to flatten out with heavy loads. Compared to polyurethane, Thermoplastic rubber treads are softer, harder to move, less permanent, less abrasion resistant, less resistant to grease, oil, and other chemicals.