PS15X-B is a self-powered 15" coaxial musical instrument speaker well matched to acoustic instruments of all types, electric bass, or synthesizers. The red dust cap indicates a Coaxial driver that includes a rear vented 15" cone for lows and mids, a crossover network, and a 1" titanium diaphragm compression driver for extending the high frequency response. It has damped spring loaded handles, a coated steel grille, and an 18mm thick birch plywood cabinet finished with hand rubbed oil, making it a beautiful, portable and durable system.