This 7-Piece Swaging Tool Drill Bit Set is perfect for HVAC repairing, which is also called air conditioner manual copper tube expanding pipe swage. It can expand the inner diameter of aluminum and copper pipes. The kit includes the most commonly used sizes of 14", 5/16", 3/8", 1/2", 5/8", 3/4", 7/8" drill bits, which can meet your different needs. This is a must-have tool set for HVAC technicians, engineers, or DIY users. The swaging tool kit is made of high quality steel, with a durable and long-lasting performance. The surface is blackened and rust-proof. The swaging tool is easy to use and operate, which is an ideal choice for HVAC systems.