Techniks 08520-09.0 | 15.90mm Diameter ER20 Black Gold Coolant RingTechniks mission is to provide high quality and innovative solutions that optimize manufacturing processes for customers engaged in metalworking, composites machining, and woodworking to meet the most challenging applications, improve machining processes, and create cost efficiencies. Black Gold Coolant Rings provide concentrated coolant on the tool path. Compatible with both Solid and Coolant Thru Cutting Tools. Coolant Rings snap into the ER Nut to