Apparatus and method for producing at high efficiency vaporization a precisely controllable, continuously adjustable gas-phase flow of a vaporizable liquid in a carrier gas are disclosed. The device exploits the shrinkage of the gel-matrix and translates this into movement of the device thereby providing a visual cue as to the condition of the gel matrix and in particular when it is exhausted. There are also disclosed a centralizing means which allows for accurate placement of the means for apply pressure to the top of the hand and also a means for further spreading and fixing the spread in the carpal tunnel region.