Dewalt D215854 Copper rings for use with 1 1/4 Inch drill bit between the drill and the Crown for greater ease of fitting and to remove it effortlessly after use. ? For use with 1-1/4 Inch drill bit to remove it easily after use ? 5 Copper ring for 1-1/4 Inch core bits. ? To fit D21583K and D21585 Diamond Drills.