Powercall Sirens custom made aluminum signs are a great way to decorate and show your devotion to you trade, you hobby or to express you opinion. These Aluminum signs are actual street sign thickness. They are not plastic, but actual 0.80 thickness street signs. They are made to last and are the best street sign's on the market. This aluminum blank has been pre-painted with Alumet's Ultra White which yields a WHITER and BRIGHTER finish for your illumination and printing needs. This blank has 1 1/2" radius round corners and 3/8" holes for easy mounting on u-channels. This blank is designed to be mounted vertically so the 3/8" holes are centered on the 12" sides (1 1/2" in from the edge).