An excellent set at a very affordable price. This set includes everything you need when maintaining your pondxpert easyfilter 4500 replacement foams for filtering out the sludge in your pond, replacement uvc bulbs to keep the dreaded green water algae at bay, and gel balls to help replenish the bacteria in your pond while clarifying the water.this set contains the following components please click links below for more information br • pondxpert easyfilter 4500 foams set of 2 br • 7w single ended uvc bulbs x2 br • pondxpert pond gel balls 500ml usual selling price when buying components individually is £36.97.