This beaker mug is made from our laboratory grade beakers, but we added a handle and vacuum jacketed it. The vacuum jacket is an insulating layer which limits conduction of heat and insulates your hot or cold drink. Silvering will reflect infrared heat and when used in conjunction with vacuum jacketing the two will provide the most robust and complete insulation. These same techniques are commonly used to make ultra-insulated containers for holding and insulating liquid nitrogen. In fact the original insulated containers "thermos" were made from the same manufacturing method (silvered glass with vacuum jacket).