The Wine-StoneTM at the end of the extended tube is not really a stone but a valve. It is a specially formulated perforated and processed, pure 18-10 stainless steel module that refines the air pumped in into very tiny bubbles. The valve is food safe and free from the possibility of oxidation, corrosion, rust, stain, odor or coloration. To use with bottle, insert the Wine-StoneTM into the wine bottle. Pump ever so slowly no more than 2 or 3 times. To use with glass, pump only once. That is just enough to soften the tannins and bring out the natural flavor inherent to the wine. Comes with a wall hanger. 12-1/4"L, 2-1/8" W at pump.