NMC OSHA sign. Header "CAUTION" and legend "MICROWAVE OVEN IN USE". OSHA signs are the perfect way to alert your employees and guests when a hazard is present in your facility. Keep your facility safe, buy an OSHA regulated sign. It prevent an accident. These OSHA signs comply with OSHA 29 CFR 1910.178. Rigid plastic - 0.050 thick polystyrene material is ideal for long lasting indoor or outdoor use. Signs are supplied with radius corners and pre-drilled corner mounting holes. Good chemical resistant. Mounting sign. Maximum temperature: 183 degrees F. Black on yellow color. Measures 10-inches length by 7-inches height.