I've been reading a lot about these and haven't seen any mounted on an AR with rails. Do you need a specific mount?

I have my 250 mounted on the small rails on top of my PEPR using this: http://www.cheaperthandirt.com/ARR372-1.html . It works well, and requires no tools. Easy going from day to night hunting.

triggerdan - nice find that's a lot cheaper and does look the same. The specs say it uses Cree LED (good stuff), so it's probaby the same MFG in China that makes the EWT.

Here's an interesting read on the place in China:
http://www.ohiosportsman.com/forum/showthread.php?t=42660