LSR-SUREFLOW Side Mount Filters. The SUREFLOW is the largest selling and most popular residential pool filter sold and installed in Britain for more than 20 years. Over a quarter of a million have been commissioned. The LSR range is ideally suited to permanent in-ground residential indoor or outdoor pools. The main tank structure is made from extremely hard wearing (injection moulded) glass reinforced polyester. The smooth high gloss internal and external finish ensures a free flow and easy cleaning. The side mounted multi-port valve configuration together with the large clear lid access (230mm diameter) allows servicing of interior without the need to disturb the connecting pipe-work. The clear lid provides an excellent visual display of the water passing through. Particularly useful when back-washing the filter. Combined with the low head loss under-drain systems and connection pipe-work an LSR filter is one of the most efficient and cost.