The finest protection a bag can offer! Soundwear Performer Series Bass Trombone Gig Bags feature 1 outside foam padding, plus a 1/2" high density foam insert to protect your investment from dings or dents. This bag accommodates up to an 11 1/4 bell diameter. All brass instrument bags made by Soundwear feature the exclusive Bell Impact Protection System (BIPS). BIPS is designed to protect the most sensitive part of your instrument, the bell! The ABS plastic frame is located between the 1 foam and 1/2 high density foam insert. BIPS combines the comfort of a bag with the protection of a hard case.