Dual OMRON Relay 7812+UPC1237 Speaker Protection Board Kit for HIFI DIY AC X7B2,7812+UPC1237 Speaker Protection Board Kit for HIFI DIY AC X7B2 Dual OMRON Relay, power anti-shock function, Precision CNC double-sided circuit board tin small size, easy installed,UPC1237 best performance as core devices, with power-on delay and DC protection.DIY AC X7B2 Dual OMRON Relay 7812+UPC1237 Speaker Protection Board Kit for HIFI.