Resideo 198799Z/U Outdoor/Supply Sensor, For Use With AQ475, AQ675 and AQ775 Aquastat Controller, 2.620 +/- 0.015 in Insertion, 0.375 +/- 0.002 in Bulb Dia, Copper Bulb for SOLA Hydronic Control, 42 in L Capillary, Import