SMAKN&reg; UPC1237 Stereo Speaker Protection Finished Board Components DIY Start up delay about 3 seconds. DC protection (when DC&gt;=1V). Circuit is simple, easily to DIY. Operating voltage: AC(12-15V) about 5W Independent power supply. PCB size: 69mm*36mm*1.6mm. Finished size: 69mm*36mm*25mm.