along with the G1265, the G12S50 graced many a JCM800 cabinet and combo! These share a magnet with the old greenback S speakers I like but have more than twice the power handling and a more modern sound, but still very good. One should always have a few of these in the closet, they have a distinctly early 80s trash rock flavor in pairs or quads. Efficiency is about the same as a 'pre-rola' G12M greenback. So not too loud.