Lincoln K and KP Numbers › Lincoln Electric KP4781-1-B25 DIFFUSER, THREAD-ON, 550A, EXT. REACH Lincoln Electric KP4781-1-B25 DIFFUSER, THREAD-ON, 550A, EXT. REACH Sale Price: $584.82 Original Price: $655.00 DIFFUSER, THREAD-ON, 550A, EXT. REACH PURCHASE PRICE SHOWN IS FOR A QUANTITY OF 25.000 Add To Cart Added! DIFFUSER, THREAD-ON, 550A, EXT. REACH PURCHASE PRICE SHOWN IS FOR A QUANTITY OF 25.000