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 prolong its service life. SIZE: The total size is 24 x 14mm, and the clamping range is 0.4-3.2mm, 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 9/32-40 thread, 6.2mm direct 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 not be used, it can match the thread, but the machine shaft is too short. Good metal texture, comfortable surface. -- The single thrust bearing can easily convert the torque applied by the handle into a higher holding force. -- Easy to use and install. Convenient, safe and quick. -- The chuck can be replaced quickly and easily without having to replace the chuck. -- Lock and release the bit easily. Allows the use of conventional drill bits to drive power tools. SPECIFICATION: Weight: 0.1 Kg Material : Aluminum Alloy Color: Black Quantity: 4 Pieces Category: Electric Suction Cup Total Length: 23.4 mm Tooth width: 0.75mm pitch Clamping range: 0.4-3.2mm Clamping range: 0, 4-3.4mm Length: 2.1cm, Diameter: 1.4cm Use with Rotary Tool Models: 4000 , 400, 3000, 398, 395, 300, 285, 275, 200, 100, 8220, 8200, 800, 780, 770, 7700, 750 (Note: Make sure the rotary tool model is listed in the list .) PACKAGE INCLUDED: 4 X Keyless Rotary Chuck