NMC OSHA signs are the perfect way to alert your employees and guests when a hazard is present in your facility. Header "DANGER" and legend "ALL DRIVERS MUST CHOCK WHEELS". These OSHA signs comply with OSHA 29 CFR 1910.145. Rigid plastic 0.050 thick polystyrene material is ideal for long lasting indoor or outdoor use. Good chemical resistant. Maximum temperature: 183 degree F. Mounting: yes. Measures 20-inches length by 14-inches height.