Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number R27-4 found under Holder Electrical Contact Ring by Conductix Inc. The National Stock Number assigned to this part is 5977005520588, and the Federal Supply Class is 5977 Electrical Contact Brushes And Electrodes. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like R27-4.