0.3 - 6.5mm The chuck is small and lightweight, which won't bring extra burden to your operation Easily convert your cordless electric screwdriver into a drill to quickly switch between different tasks, reducing time needed for a project 1/4inch hex shank fits more easily and securely in power tools Classic 3-jaw keyed design securely holds a wide range of twist drill bits in a convenient way; Versatile use on hammer drills and electric screwdrivers to quickly change tasks and keep the job moving; Features: Suitable accessories: Easy to use and easy to install, safe, fast, 1/4 inch hex key card is easy access to electric screwdriver. Function: These keyless drill chucks can easily transform electric screwdriver without wire in drill or grinder to perform quick switching tasks and maintain work progress; They are must-have accessories for power tools. Wide Range of Applications: These drill chucks have various specifications and can be matched with most cordless electric drills and screwdrivers. They can be applied in cars, garages, warehouses, offices, homes, etc. Easy loading and unloading: This keyless chuck converter can change from driving to drilling in seconds, and also gives you the freedom to drill with one hand, which is great for working in tight spaces. Features: Material: Metal Color: Black, Silver Package includes : 2 x keyless chucks