If the Briefcase Ultimate is the formula one race car of the PJB family, then the Briefcase Signature it its refined twin sister. Exuding in luxury, like a fine instrument, the cabinet is hand polished to a mirror finish in Sunburst Sapele Mahogany wood. Each Signature amplifier comes with a signed certified calibration certificate by designer and founder Phil Jones. To some this amplifier may well be considered an instrument of sonic perfection. So it supplied with a custom PJB rugged wheeled case to give it the Ultimate protection to last a lifetime of musical and visual pleasure.