Here's a pre-owned Vincent Bach Stradivarius Model 42 F-trigger trombone with a sticky slide.  The serial number on the horn is 81xxx and the serial number on the slide is 131xxx.  On the bell it reads, "Stradivarius Model 42 Vincent Bach Elkhart, IN. USA" and the serial number and "Model 42" is stamped on the slide. (see pic)  It has; free moving tuning slides, good valve, 8 1/2" bell, mouthpiece and a case.  The bell has a few dings and little crinkle. (see pic/easy fix)  The slide is sticky/sluggish.  The slide has no spots.  It sluggish like a slide that has a ding but my untrained eye can't find one.  It has the wear of a used horn but all-in-all looks solid and would detail nicely.  Me?  I'm not a store/repairman.  Buy accordingly.  Looking for instruments and getting them into the hands of players is a hobby of mine.  I've come across a few of these in the past and they are well liked.  I'm not a trombone player but can get a nice sound out of it but, again, you'll want to have you tech take out the dings and get the slide working perfectly/give the works...and am selling as such.  No question, a skilled hand could make it sing.  Get it mint and swing. It's cool.  I'm proud to offer it and you'll be proud to own it.  Thanks for your interest and best of luck.