The cylinder can be used for Raspberry Pi. It protects Raspberry Pi from such as short-circuit.Features Compatible with Raspberry Pi A+,B,B+/2. Screw Diameter: M2.5 Cylinder Length: 15mm Thread lenght: 6mm M2.5 NutPart List M2.5 Copper Cylinders x 4 M2.5 Nut x 4