Delta Faucet Ara 17 Series 6-Setting Integrated Diverter Valve Trim Kit, Brushed Nickel Diverter Valve Trim Kit, Shower Trim Kit, Stainless T27967-SS (Valve Not Included) - Amazon.com
Delta 1/2-in ID x 1/2-in OD Brass Diverter Valve in the Tub & Shower Valves department at Lowes.com