6-IN-1 KIT: Common size combinations extend the reach and capacity of your jack system, making this kit extremely versatile for a variety of repair needs. DESIGN: The adapter's spring-loaded ball securely locks the sleeve, allowing you to get the most out of this handy adapter and reducer set and ensuring you always have the right size for the job. PREMIUM MATERIALS: These adapters and reducers are made from high-strength, heat-treated chrome vanadium steel. The nickel/chrome plated surface resists corrosion, eliminating any risk of rust and ensuring a long service life for tools used in industrial, mechanical or construction work. Easy to store: The plastic box can easily store and transport all components, which is very convenient for your daily use. Specifications: 1/4 3/8 1/2 3/4 1 inch interchangeable Surface treatment: black phosphating Material: 42CR-MO Hardness: (HRC) 40 2 The material of the sleeve conversion joint is chrome vanadium alloy steel, which is forged as a whole. The surface is black phosphated and quenched as a whole. 3/8 hole 1/4 head: 18g 1/4 hole 3/8 head: 18g 3/8 hole 1/2 head: 43g 1/2 hole 3/8 head: 47g 3/4 hole 2/1 head: 253g 1/2 hole 3/4 head: 136g Note: The data are all measured manually, please allow 1-3cm error due to differences in light and display, there may be some color differences, please refer to the actual item received.