18650 Cylinder Cell Assembly Materials possesses 18mm x 65mm dimensions where different components are involved in its manufacture and assembly. Its case is considered the most important part of cylinder cells assembly, which is available with an anti-explosive case. It is equipped with a built-in PTC thermistor for overcurrent protection. It is made up of Nickel-plated A3 steel and seals O-ring, and the spacer is made of nylon. Nickel strips are highly corrosive resistant. Pure Nickel is rust-resistant when applied to batteries.