The square downpipe filter boasts an incredibly high water yield of approximately 90%! This diverter can be installed in minutes to downpipes of 70mm to 100mm diameter. All you need to do is saw a section of your downpipe to allow the diverter to sit comfortably in place. The downpipe filter will then filter any debris from your roof, moss, leaves, etc. and stop it from getting into your water butt. The square downpipe filter allows your to protect your water butt from a hard frost as you can stop the flow of rainwater into your water butt, thanks to the easy to use switch located on the side of the diverter.