Oregon Scientific makes many models of Temperature and Humidity sensors both under their own name and OEM'ed for other companies like radio shack. Though there is no guarantee if the case and options are the same as any of these units it will likely work. These are the model numbers of devices I know for certain to work:
If you have a device that has multiple readings remember to create a Unit in XTension for each reading of the device on the same address. So for a humidity/temperature device create 2 units with the device type set to the appropriate sensor input but the same address.