Lincoln Service Parts 1 › Lincoln Electric 9SL7390-1 POLARITY SWITCH ASBLY L7390-1 Lincoln Electric 9SL7390-1 POLARITY SWITCH ASBLY L7390-1 Sale Price: $810.26 Original Price: $931.80 POLARITY SWITCH ASBLY PURCHASE PRICE SHOWN IS FOR A QUANTITY OF 1 Add To Cart Added! POLARITY SWITCH ASBLY PURCHASE PRICE SHOWN IS FOR A QUANTITY OF 1