heres a new HID on ebay

Not a bad thing Li-ion batteries are used in cell phones laptops and a lot of HID flashlights. It depends on how it is re/discharged how safe it is. The battery is meant for this flashlight only (so it is harder to get a replacement after max. 500 recharges).
So you should buy an extra pack

My personal thought is that a 10w HID is not so practical
You better get a 500 lumen (3x) Cree light.
Or if you need the throw ; get a 35W HID
 
If you look closely to the picture, the battery looks like three cylindrical cells shrink-wrapped together in a holder. Since it's probably a 12 volt ballast, three cells would indicate li-ion. The cells themselves are probably 18650 or 17670.

$225 USD asking price plus shipping is a bit steep for a light of this type, considering it is an unknown brand and relatively unknown (to CPFers) vendor.
 
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