For power control of heating mantles of the HM series, electric Bunsen burners and heating tapes. Each controller has two neon indicators: White neon "Power On" and amber neon "Mantle/Bunsen Heater On". When the control knob is turned clockwise, the power increases and the amber indicator light begins to pulse. As soon as the maximum power is reached, the lamp lights up continuously. There is a clamp on the rear of the controller for attaching a rod (Ø 12 mm).