The Grit Guard Insert fits in the bottom of your wash bucket and separates the grit from the mitt! The inserts radial surface design extracts particles such as dirt, grit and grime from your wash mitt, providing a clean, scratch-free wash mitt every time you go back to the bucket for water. All of the potentially harmful dirt settle in the bottom of the bucket, keeping it out of your mitt and off of your paint. This simple and cost effective method protects your precious painted surfaces from being scratched and saves your paint from swirl marks and scratches. Fits most 3.5 to 7 gallon buckets.