Use this Pro 1100 brush for the Quick-Strip Single Slot brush 375mm / 65mm if you don't need to buy a full set but only need a few brushes. Here you are buying 1 brush at a time so you have to change the quantity of brushes by changing the quantity on the check out page. If you need 40 brushes change it to 40 pieces from the 1 piece it will start out with.