Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 49-005-250-020 found under Reference Standard Blood Chemistry by Serono Baker Diagnostics Inc. The National Stock Number assigned to this part is 6550012870630, and the Federal Supply Class is . Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 49-005-250-020.