carriers for flat objects such as sheet music are described which supplement the capacity of musical instrument cases having at least one handle . an adjustable hanger strap or straps are provided so that the carrier can be used on cases having different sizes , shapes and thicknesses . the case handle fits through one of a plurality of elongated slots on the hangar strap of the carrier with the carrier positioned against the case . the particular slot used depends on the shape and size of the case . the carrier has one or more compartments for storing articles placed therein , with the carrier draping over one of the sides while being transported about as a single unit by virtue of the case carry handle . loops engaging the strap are also provided to provide stability .