[Gigermann]

To be fair, one doesn't typically run a campaign out of the X-Tech books.

I just recently ended a run of a mostly-historical campaign set in 1725 AD, and I definitely used a lot of both Low-Tech and High-Tech gear. I had to do a little research to develop an understanding of what was available at that specific year. Corrections had to be made from time to time, but we all understood that if it doesn't exist yet, it's not available.

Collecting stuff in Low/High/Ultra categories is convenient for publishing, but if you're running something in any way historical, you sometimes have to ignore that. Plus, the later the book was written, the better, more-conprehensive the rules tend to be—the "containers" are a good example of this—and in GURPS' case, they were written in reverse order.