Everything needed for a full Heliodyne assembly for a 10K sensor and 1/2" thermalwell. Includes probe style Heliodyne 10K thermistor (SENS 001 003). This sensor works with all Heliodyne Delta-T differential solar controllers, as well as most other controllers that require a 10K sensor (including Heliotrope, Goldline/Hayward, and Pentair). Brass body with 5.5" leads, rated to 392F. Also includes Heliodyne Thermalwell. 1/2" NPT pipe thread brass well, overall length is 2", length of probe is 1 1/2". Can be used in a pipe fitting or in 1/2" side port on Rheem and Sunearth HE solar tanks. Includes set screw and allen wrench to secure probe into well.