T675A has one single-pole, double-throw (SPDT) switch that breaks R-B and makes R-W at the setpoint on temperature rise;T675B manual reset low limit has one single-pole, single-throw (SPST) switch that breaks at the setpoint on a temperature fall, and requires manual setting;T678A has two single-pole, double-throw (SPDT) switches that operate in sequence;T675A models available with adjustable differential;T675A and T678A have setpoint adjustment knob on front of case;Capillary tubing allows remote mounting of sensing element, models available with various lengths;T675A and T678A models available with a fast-response sensing element;Controller can be mounted in any position;Mounting accessories available for all applications;Ambient temperature compensated