High-grade jacket materials such as polyurethane (PUR) should be considered. PUR is resistant to harsh conditions such as oils, fire, abrasions and chemicals. Lower grade jacket materials, such as PVC, while less expensive cannot handle exposure to oils and chemicals and might degrade. PVC also becomes brittle and cracks at low temperatures. Material selection can be dependent on the material’s electrical, mechanical and environmental capabilities and the ease with which they can be attached to other materials through processes such as crimping, soldering and other processes. Connector materials are chosen such that they have minimal resistance, good electric conductivity, good machinability, and good stability over time and good hardness