Presto 09978 Pressure Indicator and Regulator for Most Cookers After 1957 Presto 09978 Pressure Indicator And Regulator For Most Cookers After 1957 The Pressure Regulator Fits Onto The Vent Pipe To Indicate When 15 Pounds Pressure Is Reached; And Controls Pressure In The Unit. A Gentle Rocking Motion Of The Pressure Regulator Indicates That Proper Cooking Pressure Is Being Maintained. Pressure Indicator & Regulator; For All Pressure Cookers Manufactured After 1957 Except 01/Pa4; 01/Pa6; 01/Pa4H; 01/Pa6H; 01/Pa6Hb; 01/