GB Midi Import facilitates the import of midi information from a standard midi file into GarageBand.
Other products which claim to perform this function, simply convert the midi information into sound which may then be imported.
GB Midi Import copies the actual midi data into GarageBand which can be rendered using it's internal software instruments.
Creates Apple Midi Loop information which GarageBand natively understands.
Simple drag and drop interface to move midi data between applications.