You've not linked to the product so can't comment with any degree of accuacy, however I presume it's going to a triple XM-L light.
I can however guarantee that it's gonna be nowhere near 4000 lumens. More likely 900 or so.... Still, if your only experience of flashlights is the regular stuff like Maglites etc, then you'll still probably be pretty impressed with that amount of light.
A triple XM-L light at that price is going to be built with the lowest end, bulk-buy, bargain basement materials and will likely pack up pretty quick. Make sure youre careful with Li-Ion batteries - it's worth doing some reading on the subject if this is your first forray into that world - there's tons of info on here and youll learn a lot by doing some general searching.
Welcome to the forum,
Hope you enjoy your new torch.
Tim