①. [DOUBLE LOCK] The drill bit extension has a locking device at the interface, which, together with the slight magnetism at the bottom of the hole, ensures that the screwdriver bit or drill bit is securely fastened in place and reduces the likelihood of the screwdriver bit or drill bit wobbling and falling out. The locking device on the magnetic bit holder when in use allows for quick and easy bit changes, helping to improve work efficiency. ②. [MATERIAL] The bit holder for impact driver is made of metal for hardness and durability. This drill extension bit holder is suitable for use with impact drivers or drill bit sets. ③. [UNIVERSAL USE FOR 1/4 INCH] The quick release bit holder works with most 1/4 inch blades or hex bits, and the impact bit holder itself has a 1/4 inch hex shank. This drill extension is a useful addition to a toolbox. ④. [WIDE USE] The impact extension is suitable for electric screwdrivers, pneumatic screwdrivers, hand screwdrivers, t-handle 1/4 inch screwdrivers, corded drills, cordless drills, pneumatic drills, impact drills, or any other device with a 1/4 inch hex shank. The drill bit extender is suitable for maintenance repairs or DIY work in automotive, hardware, home and other fields. ⑤. [PACKAGE CONTENT] Includes 4 locking bit holders in 4 lengths: 2 inches (60 mm), 4 inches (100 mm), 6 inches (150 mm) and 12 inches (295 mm). This magnetic drill bit holder provides options for different situations, whether for general projects or more complex tasks. ⑥. Colour: Black & Red ⑦. Material: Metal ⑧. Package Contents: 4 * Drill Bit Extension ⑨. Only the above package content is included; other products are not included. ⑩. Note: Light reflection and different displays may cause the color of the item in the picture to differ slightly from the real thing. The measurement allowed error is +/- 1-3cm.