Our glass items are hand blown glass (silicate)and decorated with a lead free baked on enamel. When we introduced our Inked line, we were overwhelmed with demand, and suggestions for further items in that range. Glass is not something we have embraced totally as a company, but we had many requests for this particular item.We decided to make two shapes...a Probe and a Dual Probe. The Probe has a base,but not large enough for secure use with a harness.