Protect Your InstrumentHighly impact resistantA specially formulated hard foam is used. This foam is expensive, dense, and highly impact resistant. The foam is tested by bouncing a 300gm glass ball on the foam laid over a glass plate. Only if the glass ball or glass plate does not break, chip or crack, then the foam is approved for use. Ordinary bags use soft foam, which does not protect.No Gap Under ZipperFor all-around total protection there is no gap under the zipper. A band of thick hard foam is sewn under the zipper (zipper guard). This zipper guard prevents the music instrument from damage by impact or by scratches from the zipper. In ordinary bags there is a gap in foam protection under the zipper. Without any protection the music instrument is easily damaged by any impact on the zipper. It is also easily scratched by the zipper.