Rarely offered! This was a previous pair of M1A monoblocks that were sent in and upgraded to a FET front end from HERRON AUDIO. The FET front end topology is utilized in the M2 monoblocks. Great sounding amp, especially with companion preamplifier. This was used with the Herron audio VTSP 3a-R03 preamp using herron audio interconnects. It was a M1a unit originally, and I sent it in in February 2018 to get it upgraded by Keith Herron. You can confirm this by telling him the serial number(A243 and A244) as he keeps very detailed records of all of his units. These monoblocks have seen very little use. Excellent condition. I do NOT see any marks or scratches. All original factory boxes are included. Shipping will be $150 for the pair. Paypal adds 3%.