Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number RT100-A1 UPPER ASSY found under Regulator Thermosta by Robertshaw Controls Company. The National Stock Number assigned to this part is 4820014145581, and the Federal Supply Class is 4820 Valves Nonpowered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like RT100-A1 UPPER ASSY.