This is a bass trombone mouthpiece. I purchased it a few months ago and used it a few times before storing it. There are slight scratches from use, but it's almost like new. The threads move smoothly and can be removed. It is compatible with the Aria cup and backbore I am selling separately, and can be exchanged. In my personal opinion, both Aria and Obligato felt larger than other companies' mouthpieces of the same size, perhaps due to the rounded rim. Rounded rims usually give the impression of a blurry sound, but perhaps because of the V-cup-like shape, the articulation was rather clear. It was crisp yet rich with a lot of resonance, a tone I'd never experienced before. When playing alone, it seemed suitable for solos, but when playing with others, it was surprisingly easy for others to play along, which was unexpected. Also, the overall length should be longer than a standard mouthpiece, but for some reason, the pitch is higher than other companies' mouthpieces of the same size. Obligato gives the impression of a larger volume and tone scale compared to Aria. Perhaps because of this, the Pollard Signature backbore seems to match better than the more compact B2. Please consider this opportunity. Long Island Brass Pollard Sarastro Obligato 900 Rim Inner Diameter: 29mm Throat: 0.312in Backbore: Pollard Signature Obligato is designed to play a key role as an important member of the low brass section. A more traditional feel and moderate resistance allow for sharp, quick entrances while maintaining a rich and powerful tone. It is the second largest of the four Pollard models and seems to be designed for all-around use in an orchestra. Pollard Signature Backbore Our most open backbore, combined with the newly designed high-pressure cup, provides a smooth playing feel. Compatible with all bass trombone mouthpiece models.