I did check it out on the web and found some good reports.
That used 4501 went for $95.30 last night.
I'm reluctant to spent that much, since these;
are available New for $114, and one of these might be suitable for my needs.
What model did you buy?
Oh yeah, yesterday I picked up some fittings that I can use to make
a micro Bell-Jar experiment. I'll mess with that today, since my
3 quarts of RobinAir vacuum pump oil is coming in today.