Maker's Name: 
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7.5 × 7.5 × 23.5 cm

This glass vessel is designed to maintain liquids hot or cold for a long period, by reducing the transfer of heat into or out of the liquid.

It is a double-walled vessel, with a vacuum between the walls to reduce conduction thru and convection in gases. The internal surfaces of the glass are silvered to reduce radiation. The glass is also a poor conductor.

An insulating cork inserted in the mouth of the vessel also reduces convection loss.

It is possible to hold the vessel with bare hands when it is filled with boiling water or liquid air. This is not a recommended practice as the vessel is fragile, and may break when bumped, spilling the contents.