Prevenz Antimicrobial tread material. X-treme Plus Solid Elastomer Wheel - XP. Heavy duty versionof XI wheel. Designed specifically for high-capacity manual applications involving chemicals, solvents or water. X-tremely low rolling resistance provides the ergonomic qualities you demand. One-piece construction affords freedom from tread separation with an exceptionally long life. Non-marking, floor protective tread. Hardness: 60 Shore D. Premium Polyurethane. Excellent for towing applications. Wheel Face: Moderate crown. Finish: XP Grey. Temperature Range: up to +250 degrees Fahrenheit.