This fits your .
520-2459C Features: -Showers function with equal pressure simultaneously or separately. -Fits all standard shower arms. -Chrome finish. Product Type: -Diverter valve. Valve Application: -Shower valve. Primary Material: -Plastic. Connection Type: -Slip fit. Generic Specifications: -3 way diverter.
From the Manufacturer
LDR 520 2459C Universal Three-Way Shower Diverter, Chrome. Chrome Three-Way Diverter allows use of both showers at equal pressure at once, or either shower separately. Fits all standard shower arms. Easy do-it-yourself installation instructions. With Chrome Finish, Allows use of both showers at equal pressure at once, or either shower separately, Fits all standard shower arms, Easy do-it-yourself installation instructions
LDR 520 2459C Universal Three-Way Shower Diverter Chrome - B004CLZZQC