Stock replacement parts and options listed on these pages below will fit the 2300, 2310, 2315, 2317, 2318, 2320, 2327, 2328 Professional tremolos only. FYI: Patent number or not, if the mounting plate (shown at upper left of plate group) has a Kahler logo on the back or side shoulder, has a curved or straight back and mounts with 4 Phillips wood screws, it's a 23xx model.