Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 23T-21 found under Switch Thermostatic by Therm O Disc Inc. The National Stock Number assigned to this part is 5930001974295, and the Federal Supply Class is 5930 Switches. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 23T-21.