High Quality Material: Made of bearing steel, blackened surface treatment, which is rugged and durable. Great Performance: Preserve the ductility of copper/aluminum during die forging to avoid cracks and leakage. A full range of forging tools makes it easier to expand HVAC pipes.?Suitable for hard-to-reach corners and tight spaces. Tool Set: 6 piece set, with the most common HVAC pipe diameter: 1/4inch,3/8inch,1/2inch,5/8inch,3/4inch,7/8inch.Sufficient quantity, complete specifications, perfect to complete your work needs. Easy to use: When installing the air conditioner, expand the copper pipe to connect the two copper pipes with each other. (It needs to be installed on a hand drill).Easy to use, your good assistant for work and life. Application: Suitable for hard and soft copper standardized, easy to braze swaging set. The forging stopper will provide a large swaging depth to achieve a perfect fit. Specfication: Type: Tube Expander Material: Bearing Steel, Blackened Surface Treatment Size(s): 7/8inch(22.2mm), 3/4inch(19mm), 5/8inch(15.9mm), 1/2inch(12.7mm), 3/8inch(9.5mm), 1/4inch(6.3mm) Quantity: 6 Color: Black Suitable For: Hard and Soft Standardized Application: Expanding Copper Pipe