The metal clamps are made of nickel-plated iron, good electrical conductivity, easy to install. The sleeves are made of high quality PVC, high quality flame retardant, environmentally friendly and non-toxic, safe to use . Comes in total 20 clips, the length of the clip (without sleeve) is 28mm, can meet your basic needs for daily use. Clips are frequently used in physics labs at school to assemble quickly and cheaply. They are useful for connecting components to wires. Great replacement parts for repairing broken cables on test equipment and chargers or making your own low voltage jumper cables. Description: These clips are easy to install and safe for use with the covered PVC insulation sleeves. They can be used for electrical testing, repairing broken clips on test equipment and chargers, to make your own low voltage jump leads. They are also ideal for use in stereo applications or with battery, power terminals or for use on test leads, power, test, battery, multimeter test leads. Features: Sleeve Material: PVC. Clip material: nickel-plated iron. Function: electrical test. Package: 20 clips.