MATERIAL: This flexible chuck adapter is made of all metal and is very hard after high temperature heat treatment. The black rust oxide on the surface will also extend its service life. SIZE: The overall size is 24 x 14 mm and the clamping range is 0.4-3.2 mm, which is widely used for various electric drills. CONVENIENT AND EASY TO USE: Allows you to change the attachment prompt quickly and easily. There is no need to replace the chuck when changing the size. WIDE RANGE OF APPLICATIONS: Suitable for original DREMEL 9/32-40 thread, direct 6.2mm inner hole, models are 4000, 400, 3000, 398, 395, 300, 285, 275, 200, 100, 8200, 800, 780, 770, 7700 and 750 NOTE: 8050-N/18 cannot be used, it can match the thread, but the machine shaft is too short. Good metal texture, comfortable surface. -- The simple thrust bearing can easily convert the torque applied by the handle into a stronger holding force. -- Easy to use and install. Convenient, safe and fast. -- The chuck can be replaced quickly and easily without having to replace the chuck. -- Easily lock and release the drill bit. Allows the use of conventional drill bits to drive power tools. SPECIFICATION: Material: Aluminum Alloy Color: Black Quantity: 4 Pieces Category: Electric Suction Cup Total Length: 23.4 mm Tooth Width: 0.75 mm Pitch Clamping Range: 0.4-3.2 mm Clamping Range: 0.4-3.4 mm Length: 2.1 cm, Diameter: 1.4 cm Use with Rotary Tool Models: 4000, 400, 3000, 398, 395, 300, 285, 275, 200, 100, 8220, 8200, 800, 780, 770, 7700, 750 (Note: Please make sure the Dremel rotary tool model is listed.) PACKAGE INCLUDED: 4 X Keyless Rotary ChuckLonvre