Direct replacement 4-pin mono amplifier jack. Includes lock nut and washer. 

Fits Princeton Chorus, Pro 185, BXR™ Series, Stage 112SE, Ultimate Chorus™, Roc Pro™ Series, Performe™r Series, Bronco™, '94 Twin®, Princeton 112+, Deluxe 112+, Automatic™ GT, and Blues Junior™ amplifiers.