I have no personal experience using the Slingbox wireless bridge product that plugs into your electrical wall outlet, but from what I have read, it is ESSENTIAL that the two wall outlets that you use for the two wall plug-ins must be on the same phase of your electrical house current. And since, in most homes, one-half of the outlets are on one phase and the other half are on the second phase, you have a 50-50 chance of the wireless bridges NOT working correctly, until you can assure that the two outlets into which you have plugged in the wireless bridges are on the same phase. And to figure this out in your home is not necessarily straightforward -- you would have to go to the service box and turn off one phase of the two phases of the house current, then check if the outlets in which you have the wireless bridges plugged in are still both receiving power. Lots of caution if required in doing all of this -- the current/voltage in those electrical outlets can kill!
I understand that you want to get any recommendation regarding a wireless bridge in order to hook up your Slingbox PRO HD.
Nowadays, any wireless bridge will allow you to get a connection between the Slingbox and the home router. You only need to get any of the available models and hook it up to your Slingbox. This way, the Slingbox will be able to get the router's wireless signal.