The Grit Guard prevents scratches and swirls caused by washing. This drops into the bottom of a 5 Gallon Bucket and extracts grit from your wash mitt or sponge when you drag across the grate. The dirt settles at the bottom of the bucket so your wash water stays clean. The four fins at the bottom of the guard buffer and calm the water to keep the dirt from being stirred into your clean wash. The dirt falls and stays in the bottom of the bucket instead of getting spread back onto the paint.