Check the listing for details. 4mm Tube OD Brass Compression Sleeves Ferrules Brass Ferrule Insert Fitting Kit. Condition: New. Listed at 12.88 USD. 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.