Lincoln K and KP Numbers › Lincoln Electric KP4781-1 DIFFUSER, THREAD-ON, 550A, EXT. REACH Lincoln Electric KP4781-1 DIFFUSER, THREAD-ON, 550A, EXT. REACH Sale Price: $26.02 Original Price: $29.14 DIFFUSER, THREAD-ON, 550A, EXT. REACH PURCHASE PRICE SHOWN IS FOR A QUANTITY OF 1.000 Add To Cart Added! DIFFUSER, THREAD-ON, 550A, EXT. REACH PURCHASE PRICE SHOWN IS FOR A QUANTITY OF 1.000