The 2 Pack x3 Oregon 28840 Replacement Sharpening Stones are essential accessories for your chainsaw, compatible with various brands such as Craftsman, Dolmar, STIHL, and more. These gray stones have a 4-inch diameter and are designed for use with 2-stroke engines. Made of plastic and powered by batteries, these chain sharpener stones are perfect for sharpening your chainsaw blades efficiently. With a set of 3 stones included, you can easily keep your yard and garden looking neat and well-maintained.