The uv light steriliser (filter) has a unique design which feeds the water through a special helix, meaning the water does not just run through the uv but spins inside, allowing the uv more exposure before the water exits the outlet. This form of sterilising enables increased efficiency from a more-even exposure of the water to the uv. This improved uv system, the ultra violet clarifier, continues to be a key element of a well filtered clear water system. Unlike other sterilisers, this unit has three inlet / outlet's - very useful if you want to run the output to a two-fall waterfall or indeed a waterfall and a filter. The unit comes complete with three stepped hose tails to fit a variety of hose sizes. The uv clarifier also has a transparent centre panel enabling you the to check that the uv is fully operational at all times. The sterilizer is also supplied with a separate glass viewport which can be used to replace one of the hose tails for use as a one-in / one-out unit. This model comes with an advanced thermal protection feature, which automatically shuts the unit down if in danger of overheating. Once the unit has cooled down to normal temperature it will restart and continue to operate. To avoid overheating we advise that the unit is located in a sensible cool area rather than in direct sunlight or a hot / humid isolated area.