Mags, TDKKP is right it will accept any 18 or LRBA battery in diameter, to suit the barrel length (depending whether the M90 is bare or has the short extension or long extension). It is the same unit exactly as the rechargeable unit, just the rechargeable unit comes with batteries and charger in the box.
I would strongly suggest using the 18mm batteries, they usually have considerably more power than 17 series batteries. I would suggest AW, Pila or of course Wolf Eyes (as a WE dealer) batteries, you want as much power as possible backing up ang high power incan lamps. Hope you like the unit.