Plumbing - On Off Volume
American Standard 1/2 In. Rough On/Off Volume Control Valves, 1/2 In. Inlet/Outlet (Handle Not Included)
Available for about $28 (when HomeDepot has it in their frequent sales).
Or $20.70 from
http://www.amazon.com/American-Standard-R701-Control-Included/dp/B001EQA3VU/ref=pd_bxgy_hi_img_y
Check that it is low lead.
American Standard Single On/Off Volume Control Trim Kit, Metal Knob Handle (Valve Not Included)
Available for about $32.50 (when HomeDepot has it in their frequent sales).
Or from