Steps of use: 1.choose the batch head you need to use, rotate 180 degrees and pull out 2.unscrew the handle cover 3.put the batch head into the handle 4.screw the handle cover Specifications: Size of the case: 10.5 x 6.5 x 2.0 cm Length of the bits: 3.3cm Weight: 125g 24 Bits in the following sizes: 10 x Torx Screwdrivers (T2/T3/T4/T5/T6/T7/T8/T9/T10/T15) 5 x Cross Screwdrivers (1.0/1.2/1.5/2.0/3.0) 4 x Flat-blade Screwdrivers (1.0/1.5/2.0/3.0) 2 x Pentagon Screwdrivers (0.8/1.2) 1 x Y-type Screwdriver (2.0) 1 x Triangle Screwdriver (2.3) 1 x Point Screwdriver (0.8) Package Including: 10 x "✡" (Star hexagon Screwdrivers) (T2/T3/T4/T5/T6/T7/T8/T9/T10/T15) 5 x "+" (Cross Screwdrivers) (1.0/1.2/1.5/2.0/3.0) 4 x "-" (Flat-blade Screwdrivers) (1.0/1.5/2.0/3.0) 2 x "★"(Pentagon Screwdriver) (0.8/1.2)