The side brushes with brush configuration that is made up of standard bristles and bristles that are three times harder are ideal for loosening and sweeping up wet waste. We recommend that you use this, for example, to sweep up leaves that have become wet from the rain and are stuck to the ground. This authentic Kärcher accessory is compatible with the S4 Twin Push Sweeper. Note that due to the stiffer bristles to pick up wet objects, the push sweeper will require slightly more effort to push with these brushes.