The Professional 105 GCB is precision CNC machined from solid brass and is then finished with a 5 micron thick 24-karat gold plating, the screws are gold plated brass. The buttons of the 105 GCB are sapphire crystal, hand painted with 24-karat gold, to produce a front surface made entirely of sapphire crystal. Its features are the same like the 105 EM model.