Quantum Radio slave set with 4 receiver and 4i sender. With box, instructions, and transformer. The transformer works with the receiver and eliminates the need for batteries in the receiver. Just tested and working fine. This set is "Frequency D".
The units have both "household" and PC connections. Quantum says the range is about 200 ft with antenna down and 350 ft with antenna (in receiver) up.
Yes, I should have mentioned that (batteries in sending unit). No transformer for that nor would you typically want one as it would negate most of the value of being wireless.