The e250 Combination Square features a stainless steel blade and matte finish that will never rust or corrode. The True Blue vial is guaranteed accurate to within .00050 inch and carries a lifetime guarantee. Empire Level is the home of True Blue, the most accurate vials in the world. The newly designed True Blue series of levels and squares are engineered to provide maximum accuracy, extreme durability, and enhanced readability with the strongest warranty in the industry. Empire Level is the leading designer and innovator of accurate levels and measuring tools.