The internal retention material can hold up to ten times its weight of water releasing it as a vapour through precision vents cut along the length of the tube.\n\nTubes are extruded from non-vinyl and non-allergenic material. \n\nWater absorbtion stems inside Humitrons are sized for each class of instrument. \n\nEnd plugs are sealed to prevent dripping. \n\nCaps are designed for each instrument to keep Humitrons in position.\n\nQuantity and size of holes are calculated for gradual and effective release of moisture.\n\nTubes are flexible to place Humitrons easily inside instruments and rigid enough not to lay flat.\n\nMade in USA by RDM