It looks like an elongated EA4 with 26650 support. Interesting. A single 26650 in the 4200mAh region could last just as long as 4xAA 2000mAh NiMH.
Of course, I really do not expect this to have the right driver (with boost) to maintain full brightness all the way to cell depletion.
Reflector
Large OD 36.4mm 38.9mm
Reflector
Large ID 32.5mm 33.5mm
Reflector
OAL 28.5mm 28.5mm
Reflector
LED hole 8.6mm 8.85mm
So this one is Dimensions: 5.00 in x 1.57 in x 5.00 in (12.7 cm x 4.0 cm x 12.7 cm) Just a little longer, but not much and about the same diameter. Looks like an EA4 clone to me, but for Li-ions. Good find, now it needs to be torn down and inspected, followed by modding it to it's full potential.
No, not me, I'm broke for the next few months, one of you guys need to get it and mod it.
To me I think it's more of a black Rook that runs on a single 26650 which is what the Rook should have run in the first place. I do see a resemblance to the EA4 though.