Made of steel, good workmanship, high precision.Magnetism: Strong magnetismMaterial: Metal2 X Magnetizer RingSystem: MetricUse it to magnetize the 6.35mm batch head.Anti-impact and hard, great wear .Insulation: NoStrong magnetism the screw from falling off.Size: 21 x 12 mmHardness: HRC60buyer: Due to lighting effects display brightness manual measurements etc. the color and size between the photo and the actual item may vary slightly. Sincerely hope that you can understand! Thank you!Screw head: purposeExplosion-proof: No100% new high quality.