This brass compression sleeves ferrule is widely used in pipe connection for hydraulic and pneumatic systems, HVAC, humidifiers, etc., suitable for connecting copper, brass, aluminum, or plastic tubing.Specification:Color: Brass ToneMaterial: BrassSleeves Ferrule Size: 4mmx5.5mmx4mm / 0.16"x0.22"x0.16"(ID*OD*H)Insert Fitting Size: 2mmx3.8mmx10.5mm / 0.08"x0.15"x0.41"(ID*OD*H)Suitable for connecting 4mm pipe.Packing List: 10 Pack x Brass Ferrule, 10 Pack x Insert FittingAdvantage:The brass ferrule fittings are made of brass, it is durable and reusable.These ferrules have a smooth surface and provide a good seal, providing a secure connection for pipe connections.Instruction:Insert the copper pipe with the appropriate diameter into the sleeve, then fixing it to pipe connectors with nuts.NOTE: Please confirm the pipe size before purchasing.