I got a new pair of these Li-ion 9V rechargeables to maybe replace the 2-9V alkaline power supply I use to power my NAK MX-100 mixer. Gonna hack the cables tomorrow and solder the ends into a 4-pin female mic connector, like the 2 alkalines are setup now. There's no power switch on the mixer, so I'll be plugging in hot ---- hope the current surge doesn't pop the protection circuit, or else I'll be back to using alkalines again. I suppose one could make up a 12V sled of AAA batteries to jumpstart a Li-ion, though.........it would save having to search around for AC. I'll let you know if this works for me......