Protec s Deluxe Viola PRO PAC Case utilizes an adjustable shoulder block secured by hook n loop fasteners to fit violas from 13 to 17.5. Each PRO PAC case features a water resistant Ballistic Nylon exterior large front pocket subway handle backside sheet music pocket padded shoulder strap and ID tag soft molded interior Protec microfiber cloth blanket 2 bow clips and a shoulder rest storage strap. Comfort Features Carry handle features a padded grip secured by a hook n loop closure Quick-lock closure Backpackable with optional backpack strap (model #BPSTRAP) Includes padded shoulder strap and ID tag Subway handle strap with contoured rubber grip Interior Features Soft molded interior Soft non-abrasive velvoa lining Bow clips 2 Suspension padding Adjustable shoulder block Shoulder rest storage strap Large accessory compartment Exterior Features Built-in organizer with two interior sleeves to hold pens keys and small accessories Backside sheet music pocket Rubber feet Large front pocket zippered Large rear pocket zippered Water-resistant 1680D ballistic nylon exterior