Murray 20 Amp 6.5 in. Whole House Surge Protected Circuit Breaker Comprised of a highly effective TVSS integrated with 2 single-pole 20 Amp circuit breakers 2 green LED indicator lights show when surge protection is provided Utilizes 150 VAC, 40 mm metal oxide varistors- 40kA maximum impulse rating Maximum impulse rating for the SPD module is 40kA, the standard interrupting rating for circuit breakers is 10K AIC