These are fantastic sounding monoblocks that operate from a Lithio pure DC power supply inside of each amplifier. The SmartSupply for charging is included with the amps with 2 long umbilical cords. Turn the amps off after use and the batteries automatically recharge from the SmartSupply charging unit.
A single charge provides around 40+ hours of operation. There are toggles so you can switch phase and lift the ground - handy if you have any hum issues.
Loudspeaker Connections are a pair of WBT Binding Posts (Accepts Spades / Pins / Bare Wire). As you'd expect with battery operation, these amps are dead quiet with sound emerging from an inky black background.
I've used the successfully with a variety of different speakers, including 106dB open baffle speakers - they were dead silent even with these super efficient speakers. They'll also power difficult loads, I have them running a pair of Logans presently that dip to 0.6ohms and they sound fantastic. These are hybrid monoblocks, they operate with a pair of 6H30 input tubes transformer coupled to a bridged solid state output, delivering 320 Watts into 8 Ohms and 400 W into 4 Ohms. The condition on these is excellent, I can't see any marks or blemishes, the chrome work on the fronts looks new.
I believe mine are the next serial number up from the ones on SkyFi and in every bit as good condition, but my price is a little more affordable. The Saetta's are rich and musical and the highs are super-sweet. My Piega speakers run AMT ribbon tweeters so you can hear any harshness immediately, and these amps sound as sweet as a pea. They throw a big soundstage and image great. I'm changing direction to high-eff horns and SET amps, so these must go, reluctantly.