The HSS-ECO Slot Countersink Ø15-20 90° Size 4 is a precision tool designed for creating countersunk holes with a 90° angle. It is made from HSS (High-Speed Steel), providing excellent wear resistance and durability for heavy-duty applications. The Ø15-20 refers to the diameter range of the countersink, suitable for use on materials like metal, wood, or plastic. 90° angle: Ensures the countersink is ideal for seating flat-head screws or bolts. Size 4: Refers to the specific size designation or the cutting geometry of the tool, offering a particular range of hole sizes or cutting depth. HSS-ECO coating: Offers enhanced performance by reducing heat build-up and improving tool life. This tool is commonly used in machining, metalworking, and other applications where precise countersinking is required. It ensures clean, accurate cuts and smooth finishes for professional-grade results.