We've never seen anything quite like these little glass vials, which means they must have myriad uses, particularly at this price. The vial is 1-9/16" tall x 5/8" dia with a shoulder and a 1/4" ID lipped mouth on the top, leading into a 7/8" deep, conical cavity. The bottom has a 7/16" dia mouth, with an internal lip, and opens into a cavity around the little conical reservior. So you can fill either end. Which would hold maybe a couple of a cc one way, or 1/8 oz the other way. We're thinking obscure lab experiments, or chimneys for streetlamps in model railroads.