General description Capillary copper tube Roll of 15 meters with an interior diameter of 1mm and an exterior diameter of 2mm. It is primarily used in refrigeration systems. Technical specifications Length: 15 meters Interior diameter: 1mm Exterior diameter: 2mm Usage This capillary tube functions as a simple type of expansion device. It allows for a significant pressure drop, enabling the refrigerant to expand at the exit to the evaporator, thus maintaining the necessary pressure in a reduced volume.