Pro Tec Contoured Tenor Trombone PRO PAC Case The Universal Contoured Tenor Trombone PRO PAC Cases have been completely redesigned. The case is now streamlined and are simply terrific. Designed to fit most tenors with F-attachments, it also accommodates up to 9.5" bells. The interior features velvet lining, soft padding, tie down straps secured by hook 'n loop, accessory compartment, double mouthpiece section, and padded slide cover.