Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 42101A found under Ring Piston by Dw Hercules Llc. The National Stock Number assigned to this part is 2805002781908, and the Federal Supply Class is 2805 Gasoline Reciprocating Engines Except Aircraft And Components. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 42101A.