The Rotary Microswitch from the company is available in two versions. On the Ignition version, the burner is ignited only in the light position from 40 degrees to 70 degrees of rotation of the gas valve spindle. Turning the knob to the light position between the stated angles closes the electrical circuit and causes ignition to take place. Outside the stated angles no ignition takes place. On the Re-ignition version, the circuit remains closed on a much wider arc from 30 degrees to 270 degrees of gas valve spindle rotation. Depressing the spindle and rotating to any position beyond 30 degrees causes ignition and the circuit remains closed to enable sparking to recommence if the separate re-ignition device detects flame absence.