"Notice - Radio Frequency Fields May Exceed Exposure Limit" Sign By SmartSign | 10" x 14" Aluminum Heavy-duty, 40 mil thick, rust-proof aluminum which is made of 96% recycled materials Durable, plastic laminate protects against weather, abrasions and chemicals 4 mounting holes for screws or nails; Rounded corners for longer life and simple installation For indoor or outdoor use 14" x 10" sign has four 3/16" mounting holes, set 1/2" from each corner; Sign has a 1/2" corner radius