Original owner; approx 2 years old in excellent condition. The Synergistic Research FEQ X4 is a single channel ultra low frequency RF pulse generator that acts as a low frequency dither to overpower ambient RF and EMI in the listening room. This results in reducing ambient noise yielding greater clarity.  The Green ATM (Atmosphere Tuning Module) aids in further extending the sound field. It sits on top of the FEQ X4. Comes with power supply,  ground cable and original box. Cost new: $1690. Will cover Paypal fee and shipping at my asking price. Will ship only to US address.