A Chinese copy of the Bach 50B2
I've heard from Roger Bartlett that it's a Chinese copy of the Yamaha 613H.
The bore was listed as 0.562".
Although the bell was given as 9", it's actually closer to 9.5". The trombone with mouthpiece weighs about 2.4 kg (5.3 lbs).
This is a double valve instrument, F/G/Eb, with independent triggers. The thumb is F, the middle finger is G, and together gets you down to near Eb. The middle finger trigger is extensible.
The main slide is smooth but seems short and really can't be used out at seventh position. The three tuning slides are tight.
The mouthpiece was called out as a 5G, but it seems to be closer to a 1G or 1.5G.
The instrument came in a Pro-tech style canvas-covered zippered case with side pouch and strap. A metal cleaning rod was included.
Overall I'm happy with the horn, especially considering the price, and am ready to become a clinician for Maestro.