Godzilla - 18 x 18 Warning Signs. A Real Sign. 10 Year 3M Warranty REFLECTIVE SHEETING: 3M Engineer Grade reflective sheeting GAUGE OF ALUMINUM (thickness): 0.063 ALODIZED ALUMINUM: Sign is Manufactured on D.O.T. Alodized Aluminum BEST PERFORMANCE: Our signs last 7-10 years in Florida UV and sunlight, are washable, completely recyclable, environment friendly Not for road use.