Many dents on brass instruments can be removed easily using these knuckle tools. The tools are designed so that they can get into many hard to reach areas, then dents can be pushed out without unnecessary hammering or over working the brass. This cuts down on the possibility of cracking or stretching the metal. With these tools you reverse the action of the impact which caused the dent. In other words, you push the metal out instead of in. This set is used on all valve ports and other small diameter crooks. It consists of five 1/4inch (6.4mm) rods, running in varying degrees from a straight rod to a 90 degree right angle. This set is used with the N80A Dent Rod Ball Set. Each rod has a threaded end which will receive a 5/16inch (7.9mm), 3/8inch (9.5mm) or a 7/16inch (11.1mm) ball. By interchanging the ball you multiply the various configuration of the rods and balls to make a total of 15 different tools at your disposal. Use N80AS. We suggest getting 5 extra N54A?s for custom bending.Each rod can be purchased seperatley