The Distinction D4000 is a simple glass water still with a silica sheathed heating element which ensures top purity distillate. The Distinction is supplied complete with a 'reservoir level control' which fits into the distillate collecting vessel and will turn off the heating element when the vessel is full. Prevents overflow if the still is inadvertently left switched on when unattended. With two independent safety thermostats to prevent over heating in the event of an interruption to the water supply.