I need to control 3 devices, via three relays. I wish to use a 4-relay/usb controller to do this.

I currently use this device but I now need three relays:

http://www.barix.com/Barionet_100/511/

My Power supply is operating at 24 VDC, with the ability to supply 2A and 120W. This device powers the three devices without any problems.

The devices draw less than 8 Watts each as far as I can ascertain. 

What should I look out for when choosing suitable relays? 

Any tips on suitable devices? I need to control the device from my Python code.

Thanks,

Barry