This model has been discountinued for some time. I've only seen the mini-spike available, which is a smaller version of the knife you mentioned. Anyway, AG Russell's site has some info on it: http://www.agrussell.com/benchmade/be-640.html
Hope that helps. I'll see if I have any other pics in my PC back home - will put them up here if i find them.
Hi Both are very nice knives. I gave a past girlfriend a 640S for an anniversary one year, it became her most favorite thing in the world, never ever went anywhere without it. Below is a picture of the 650S, and I know I have a picture of the 640S just can't find it.
DN is absolutely right, again. You might want to check current eBay listings for additional data on the 640/650 series as well as Olivier Auchard's site "www.benchmadecollector.com" -- the site is new and under construction, but he may have info on it. Good luck.
Edit --- sorry all, that should have been "www.benchmadecollector.net"
If you decide to pick one up, you might give Roger of Bayou Lafourche Knife Works a call at 1-888-225-9775 since he had them on closeout a while ago. (I got one!) I don't know if he sold all of them, but they aren't listed on his site anymore, of course.
this is one of the few knives I've gotten that really feels like it was made for other than everyday utilitarian purposes. I do not take it out in public and flick it. It is razor sharp with a needle point and an aggressive snap as it locks open.