Medium-Duty Black Brush: NOTE: THIS WILL ONLY WORK WITH THE 13" CORE MODEL (Only compatible with units purchased in 2022 and newer) Perfect for all types of hard-floor surfaces from tile to hardwood and everything in between Need something other than the heavy-duty brush that came with your Prolux Core? Try out this medium-duty brush for less abrasive cleaning! Like other Prolux Core brushes, this works great on all hard-floor surfaces. We also sell a light-duty brush for even more gentle cleaning. Think of it like a toothbrush - stiffer bristles means deeper cleaning but can also hurt your gums, so choosing the right hardness for your application is important for clean, long lasting floors! Only compatible with units purchased in 2022 and newer.