The part number HIT370596 (also listed as 370596) is a genuine OEM replacement tool spindle manufactured by HiKOKI (formerly known as Hitachi Power Tools) for several models of professional-grade 14.4V and 18V cordless driver drills and combi impact drills, such as :
HITACHI CORDLESS DRIVER DRILL DS14DBSL
HITACHI CORDLESS DRIVER DRILL DS18DBFL2
HITACHI CORDLESS DRIVER DRILL DS18DBSL