The mesh insert is designed to give maximum water volume within the stainless steel bowl by allowing cobbles or pebbles to be placed on the mesh instead of within the bowl. Placing pebbles in the bowl will reduce the water volume which intern means the bowl will require topping up on a more regualar basis. The mesh insert also hides the pump and cable. the one shown in the photo has three holes cut out this one is designed for a tripple tube water feature but the one you will recieve will adapted for the feature of your choice. This item is for the SEG2145 60cm diametre by 25cm height Stainless steel bowl.