Phidgets you get back from a Manager are informational only - you can read the serial number, class, name, etc. but they aren't opened. If you want to interact with one, you have to create a new Phidget object of the correct type and call open on it.
Usually you won't want to use the manager at all, unless you don't know what kinds of Phidgets will be used with your system. If you do know what Phidgets you want to open, just create and open them and wait for their attach events.