Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number OO-R-421 TY1SZ5 found under Hammer Pneumatic Portable by General Services Administration. The National Stock Number assigned to this part is 5130001906441, and the Federal Supply Class is 5130 Hand Tools Power Driven. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like OO-R-421 TY1SZ5.