The Sievert Pro 3488 has all the features of the 3486 but in this case it features two control valves and a trigger mechanism. The first valve opens the gas supply to enable a pilot flame to be ignited, the second valve opens the main gas supply which is operated when the trigger is pressed, and this gas is then ignited by the pilot flame, giving semi automatic ignition (known as an economiser). release the trigger and the flame returns to a pilot light. This reduces gas wastage and there is no need to keep relighting the flame.
