PARASOUND HALO A21 THX Ultra II 250 Watts at 8 ohms, 400 Watts at 4 ohms 15 Beta matched 15 amp bipolar output transistors 100,000 uf power supply filter capacitance Original owner, purchased 6 years ago. Excellent condition. Very well taken care of in pet and smoke free home. NO dings or marks or even signs of aging. If you are looking for this amp on the used market, look no further.