how much for this light?

I have a co-worker wishing to sale me his old TW4 and yes I am tempted. He told me to give him a price however I do not know what a good starting point would be for an offer. How much were these when they were being sold and about what would be a good price to pay for one now in great shape?...Also if I did buy this light could I simply buy a 2 cell body for it and have an L4?...Searching old posts I found that some L4 head units did not always work well with one cell. If this is one of the original TW4 lights will the TW4 head unit work on 2 cells as well as one?...thanks

I would think a fair price would be 130-140ish? If it is the original TW4 from tactical warehouse, I believe they were hand picked to work with one cell. They should work fine with 2 cells as well just like an L4. Also if you have rechargable 123's, you can run them at full brightness for about 20 minutes in TW4 form! hope this helps...

Any idea if there were any markings on the originals that will verify if it is indeed a TW4? If not I assume it will be just as good considering if it runs ok from one cell.

No markings for these lights that I know of. But if he has been running in that form it should be fine. TW simply opened up new L4's and simply chose the brightest ones for the one cell forms through trial and error.