The Eheim Flexible Cleaning Brush Set is suitable for cleaning all sizes of Eheim Quality Hose. It is a 160cm flexible cord with 3 different brush attachments that clip on the end. This allows for easy maintenance of your filtration hoses. It is advisable to use one of these regularly to keep hoses clear of biofilm, detritus, and blockages. Fits 9/12mm, 12/16mm, 16/22mm, 19/27mm and 25/34mm.