Digital Microprocessor Control (PID) For Highest Accuracy. ● A Variety Of Changeable Blocks. ● Special Thick Blocks Guarantee Excellent Temperature Stability. ● Standard Flat Covers For Protecting The User From Accidentally Touching A Hot Block And Spitting Tubes. ● Safety Features: - Flashing Alarm Lamp To Warn Over-temp. - Over-temperature Cut-out. - Over Temperature Safety Thermostat.