Vivelle Pure Magic 2 - Reusable/Washable Filter Material (1 sheet 650mm x 800mm). For maintaining a cleaner pond.Should not be viewed as a replacement for Vivelle Pure Magic 1. It is an additional product with it\'s own merits, which fills a gap in the market for a reuseable, washable, long life filter medium. Can be used on its own but the manufacturers recommend that Vivelle Pure Magic 1 & 2 are used together when absolutely crystal clear water will be achieved and the Vivelle Pure Magic 2 will prolong the cleaning efficiency of Vivelle Pure Magic 1 though it will still need regular replacement, especially where there is a high through-put of water. Full instructions enclosed with product.