Some people are unlucky enough to live in overly hot climes with un-air-conditioned rooms so stuffy that gallium and even cesium remain in their liquid state but, generally speaking, there are only two elements that are liquid at "room temperature"; mercury and bromine. 

Liquids tend to evaporate and bromine is especially difficult to contain. No mere screwtop jar could keep it bottled up. Even not counting its very corrosive effect eating its way out of the lid this element is a notorious "escape artist" which will exploit the tiniest crack or pore to let itself out of that prison and roam out into the air freely. And that's really a bad idea, you see, because it is extremely irritating to the lungs - so much so, in fact, that it's used for making tear gas!

For this reason bromine is one of the most toxic chemicals found in their elemental state. While the quantity offered here for collectors is very small nevertheless a strong disclaimer applies that it should be handled with care and to take all necessary precautions to avoid breaking the ampule within accidentally or otherwise.