Baost Flexible Shaft Extension Screwdriver Drill Bit Holder Link Material: Plastic + Metal This flexible shaft can be used for general formula hand drill chuck, it can also be used for electric screwdriver. Flexible shaft head can be mounted hexagonal shank (1/4 handle) the first batch, mainly used in computer chassis, electrical cabinets, furniture,electrical appliances and other narrow space screwdriver can not work in an environment operations. Length: 29cm/11.42" (Approx.), Hex Shank: 6.35mm (1/4"), Inner Hexagon Head: 6.35mm (1/4") Features: for Electronic Drill, Connecting Link, Flexible