Made from high-quality spring steel. Its special design is able to supply an added tension during cycling and enhance the durability. It can make sure the nozzle movement stable and workable. It provides 145% power during cycling. It is designed for TM M&P9L. *PS: Please note: installing parts / assemble /fitting airsoft gun will need intermediate knowledge; for expert or airsoft gunsmith. Please refer to your airsoft gunsmith for proper installation/fitting. The fitting may be needed as the condition of each airsoft gun might be different. Regular maintenance is needed for all airsoft guns in order to keep it in good working condition and reduce wear out issue on parts.