Mercury Thermoregulator ±0.02°F sensitivity Direct-reading scale in °F indicates set control temperature Control point can be set by raising and lowering electrode inside capillary Tungsten contacts are sealed in inert hydrogen under pressure Bayonet-type connection; with 24 in
long (61cm) lead wire; without relay; 3mA Differential Thermoregulator Sensitive to temperature changes as small as ±0.005°F Similar to Mercury Thermoregulator (above) except it has a -35° to +500°F operating range with a 20°F differential range Coarse and fine adjustments for precise temperature regulation Surplus mercury reservoir for changing differential range; 3mA