Tune-O-Matic mounting studs on a Rickenbacker compatible baseplate. The studs are offset to position the bridge for proper intonation (bass stud .090" behind treble stud), and the countersunk mounting slots allow adjustability in positioning.  Requires a bridge with small mounting holes; uses 6-32 studs and thumbwheels.  Stud spacing is 2-29/32" (2.906"; 73.81 mm).