Here's a 1965 Miraphone Bb 186 with two detachable bells. The recording bell is original, and the upright bell is cut from a Yamaha 201 by Dan Schultz last year (so it's a perfect fit). There are two main tuning slides: the original and a new one that's a few inches longer to compensate for the shorter upright bell. The combination of upright bell and longer tuning slide pretty much corrects the typical 186 flat D and Db, and I've really liked that combination. It has a lengthened 4th valve slide, long enough for 4th valve notes to be in tune.
This tuba spent its first 30-something years in an Arizona public school, so it's a little ... rumpled. There's a dent at the bottom bow (see pictures) and various nicks and bumps elsewhere. All the small tubing is good, the slides are straight, and the valves are brilliant -- smooth, fast, and quiet.
This horn was my ticket back to tuba playing last year, but I'm enjoying smaller tubas, now, and I hate to see this not being played, so it's time to pass it along.
Price: $2700, plus any shipping. It's in Austin, Texas, and I can drive some to meet you. PM for more information.
More pictures: https://1drv.ms/u/s!AjSV784Qkma_hdhxqkt ... A?e=ThMvXk