Singer 66-1 presser bar Simanco # 32558. Works on Singer 66-1 & 66-3 machines only as it is only Singer with this foot attachment.  Includes presser bar spring #3100 and Pressure regulating thumb screw #263B which should work on other Singer models.. Or change out your 66-4 and up to the cool 66-1 machine.

Price includes shipping.