PCN 135589 A-30-3 is a Chromalox Three-Heat Ring Heater with a Chrome Steel sheath that is rated for a maximum temperature of 1200 degrees F. This three-heat ring heater has three post terminals that split the heater into two equal circuits to be regulated separately using a temperature controller. The center terminal is the common terminal. The picture is a three-heat ring heater, and it is for reference only.

Here are the ring heater specifications:  A (inches) = 4.62, B (inches) = 2.25, C (inches) = 0.31, Watts = 550, Volts = 240, and the watt density is 17 watts per sq. inch.