Two Different Types of Thread Heads: The mounting mandrel of the die grinder is composed of a handle with two different types of thread head. This mounting arbor is mainly used to mount small diameter cut-off wheels or circular saw blades with a 3/8inch or 1/4inch core hole, with a journal length suitable for cutting discs from 0.035inch to 0.16inch thick. SizeShank dia x L: 1/4 x 1-15/16, #1 screw head dia x arbor dia x L: 3/4 x 3/8 x 5/8, #2 screw head dia x arbor dia x L: 3/4 x 1/4 x 5/8. Wide Compatibility: Cut-off wheel arbor with 1/4 inch(6.35mm) shank fits most die grinders, drill rotary tools. Easy to install and remove, it really is the perfect must-have grinder accessory. Durable: The cut-off wheel arbor is made of A3 carbon steel with a black plated finish for durability and rust resistance for long term use. Versatile: The mandrel structure can also be used to mount various other types of grinding wheels, such as grinding, sanding, cleaning, descaling, polishing grinding wheels or hss saw blades. Suitable for all kinds of working scenarios. After-sales Service: We guarantee to provide you with the most satisfactory shopping service. Whether you have any questions about our products, please contact our customer service department. We will try our best to help you solve all the problems. Package Included: As show