Our brass plated wire end terminals are made of pure red copper and have good electrical conductivity. The sleeve is made of polypropylene. And their smooth tin plating process will improve oxidation resistance and extended service life.. With self-adjustable ratchet, the crimper piler will adjust itself to the appropriate diameter for stripping terminals, which improves accuracy and reliability during crimping to avoid wasting terminals.. Ferrules can be a reliable electrical connection, preventing fraying and breaking of single stranded conductors. Insulated ferrules also support the conductor, preventing breakage due to bending, wire stress and vibration.