Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number SP-100D found under Buddy Phone Surface by Undersea Systems International Inc. The National Stock Number assigned to this part is 4220015632524, and the Federal Supply Class is 4220 Marine Lifesaving And Diving Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like SP-100D.