1. Those Screwdriver Bits are made of S2 alloy steel which is anti-impact and tough, great wear . 2. Magnetic, good workmanship, high precision. each edge can be accurately locked screws, no damage to the screw and the screwdriver head. 3. Accessible: Case container bit retention system keeps bits secure, labeled bit slots help keep your tools organized. Treatment: Heat treatment nickel plating, prevent rust. Shank: 1/4 inch hex shank 6.35mm.(Can use it manually or use it for cordless screwdrivers) Length: 150mm Use: You can use it for home, auto repair, electrical repair, electronic product repair, machine repair, etc. treatment: nickel plating Specification: : T8, T10, T15, T20, T25, T27, T30, T40 Square head batch: 1.0, 2.0, 2.5, 2.7, 3.0, 4.0, 5.0 batch: 3.0PH0, 3.0PH1, 4.0PH1, 4.5PH1, 4.0PH2, 4.5PH2, 5.0PH2, 6.0PH2 One word batch: 1.6, 2.0, 2.5, 3.0, 4.0, 5.0, 6.0 Color: As Shown Material: S2 alloy steel Package Contents: 1 * Bit storage bag 30 * Bits Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.