Thank you for all the information! I payed 119.00 for it,tax in. I'm a sucker for surefire.Looks like the fat body Surefire Millennium m961, or one of its many cousins. It is likely a halogen bulb, comes with 2 extra bulbs most likely, maybe Xeon. If I remember right its 80-120ish lumen output. With halogen it burns through 3 cr123's in 30-45 minutes. Looks like it comes with with an aftermarket mount, which if it fits the old bodies, it wont fit new surefire lights without modification. last one I saw sold on ebay went for $80. If the batteries are good, they're about a buck each, I don't think the lens covers fit anything else without modification (they are nice though), the tail cap doesn't fit modern light bodies, it looks like the tape switch is missing ($60ish if you want another). Extra bulbs are $20ish. You can buy these off ebay for $150-250 or so. They're not bad lights just a little dated now.
If you wanna buy it and swap it over to LED, I suggest looking at Malkoff devices for the conversion. Very high quality. My only complaint is that you have to swap the head out and you cant use to lens covers anymore. Also changes the look a bit.
This turnkey package includes a Malkoff MDM4 Adapter and a Malkoff M61 Drop-in. The output is 450 Lumens. For a detailed description of the drop-in, see M61 under P60 Type LED Upgrades. The Malkoff MDM4 M61 Adapter will fit most Surefire Millennium Series Lights including the M3, M6, M500...malkoffdevices.com
If you wanna go that route though, I suggest we chat about buying mine. Has bag/lenses/bulbs/etc, mostly complete. I've debated selling, and I'm still on the fence. But with everything including the tape switch and malkoff conversion I would likely let it go for $275. $375 with a NIB Unity tactical surefire switch thrown in.