Grit Guard The Insert with Washboard Combo Pack (Black/Red) Includes a Red Grit Guard Insert and a Black Grit Guard Washboard. The red Grit Guard Insert is a wash insert that fits 12-inch diameter buckets to keep particles, grime, and particulates off your sponge or mitt while washing. Designed with a raised radial surface that fits in the bottom of most 3-5 gallon buckets. Works to extract grit from your wash mitt or sponge when dragged across the Grit Guard surface. The dirt then settles on the bottom of the bucket, away from your wash mitt or sponge, keeping your water clean. Dimensions: 2-1/2 x 10-3/8. The black Grit Guard Washboard works in conjunction with the Grit Guard Insert to separate grit from your wash mitt. The Grit Guard Washboard has no flat surfaces for dirt and grit to collect, like the Grit Guard Insert extracts contaminants from your cleaning tools. Rub the cleaning tool in a downward stoke against the Washboard to extract. All harmful contaminants settle at the bottom of the bucket.