All Soundwear brass instrument bags include BIPS - Bell Impact Protection System, which is an L-shaped ABS frame around the bell section of the bag to absorb all kinds of impact to the bell from any direction for increased protection and to increase the upright standing stability of the case. The Trombone Case also features a heavy-duty zipper closure, front pocket for accessories, mouthpiece pouch and detachable rucksack straps.