Prefilter compatible with for A10 a11 hero A10 a11 master cordless vacuum cleaner. Prefilter is important for suction and suction efficiency. You need to deeply clean or replace the filter regularly to prevent suction loss. The filter can be flushed. it with cold water and reinstall it after it is completely dry. Replace the filter 2 to 3 months. Depending on the frequency of use, it can be replaced for a shorter or time. The filter keeps the robot clean and reduces the penetration of dust, pollen and other allergens into the air you . Colour: as shown Material: plastic Package Contents: 2 * Filters 1 * Cleaning brush Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.