USB modules

Powered & Controlled from the USB bus.

Relays - 8 
Relay current - Up to 1Amp @30vdc or 60vac. 500mA@110vac. 250mA@250vac 
Optically isolated Inputs - 8
Input Voltage - 4.5v DC to 27v DC
Power - Powered from standard USB bus
Control interface - USB 

Controlled from the USB bus.

Relays - 8
Relay current - Up to 16Amp @24vdc or 250vac
Isolated Inputs - 8
Input Voltage - 4.5v DC to 27v DC
Power - 12V DC adaptor, supplied separately.
Control interface - USB