The newer Mars300 are 60x5w, actual watts 135w or so. 2 x 55-100v .7A drivers(some variances between different 60x5 models I had, but all similar) the older Mars300 100x3w should have 3 drivers in it, maybe 4, can't remember, but they are the same .7A drivers. Similar drivers in the Mars 2 series also.
Good for 1 x 72v cob, or 2x 36v cobs. You can also use up a little of the spare voltage with the 18v cxb15 series, I did in 2 of mine, with parallel to cut the amps down on the smaller chips.