The Barcus-Berry 3100P is a high quality Carpenter-style clamp-on jack for violin, the same jack used in the 3100 pickup system. The jack clamps onto the side of the instrument without tools, and has cork pads to protect the instrument finish. Includes jack assembly only, pickup not included.
Jack clamp range approximately 1-3/8" to 1-3/4". Fits all size violins -- does not fit violas or mandolins, for those instruments use the 3100-PV jack instead. Includes turnbuckle adjustment tool. Note: The turnbuckles are reverse-threaded on one end. If you are having trouble screwing the turnbuckle onto the jack mounting bolts, try the other end of the turnbuckle.