Up for sale here is this NOS NIB vintage GE 5642 vacuum tube. This is unused and is guaranteed to work great for you.  The box is not in great shape, but the tube itself is fine.  I have a few of these, and the tube you get may have a slightly different date code than the one in the picture.  Please see my pictures for details.

US shipping and handling is $5, and international is $18, no matter what quantity you buy. All my small parts are set up for combined shipping, so just use the "add to cart" feature and then check out all at once, and it will combine shipping. If you have any questions, please ask.

I have more tubes and other vintage electronics listed--feel free to take a look!