It is a Digital Tester/Relay Controller, Operating voltage: DC 8 ~ 28V (limitation DC 8 ~ 32V), Load capacity: maximum load capacity of relay's normally open port: DC 0 ~ 30V / 10A, AC 0 ~ 250V / 10A; maximum load capacity of relay's normally closed port: DC 0 ~ 28V / 10A, AC 0 ~ 125V / 10A, Application:Suitable for electronic equipment,industrial equipment etc.