Product description 1.[HIGH-QUALITY MATERIAL]: Hole Saw Set is made of Carbon Steel, its surface is treated with Black Oxidation. Black oxide provides mild corrosion protection to the treated parts, it is primarily used because of its aesthetic properties. 2. [High-Precision Performance]: The special gear design makes the hole more accurate and symmetrical for faster and cleaner cutting, impact resistance, wear resistance 3.[ATTENTION]: This hole saw kit is NOT suitable for HARD materials, such as density board, hardwood, metal. It is ideal for soft materials, such as plastic plate, thin pvc board, plasterboard, softwood, your ideal choice for DIY projects and household maintenance and repair 4.[11PCS SIZE INCLUDES]: (19mm),(22mm), (25mm), (32mm), (38mm), (44mm),(54mm), (64mm). 5.[16PCS SIZE INCLUDES]: (19mm), (22mm), (25mm),(28mm), (32mm), (38mm), (44mm), (54mm), (64mm), (76mm), (89mm), (102mm), (127mm). 6. [EASY ORGANIZATION]: Set includes the hole saw kit holder with size index for easy storage and organizing. It is designed to keep all components organized and convenient to take.