Fire-King Early 1940s Block Letter Stamp Ivory Flat Bottom Shaving Mug Condition: USED Color: Ivory Stamp: Fire-King OVEN GLASS Production Period: 1940s Weight: 284g Height: 9.2mm (5mm taller than usual) There are small scratches and scuffs, but no cracks or chips are visible. It's a relatively clean flat-bottom mug for something from the 1940s. ▶︎▶︎▶︎ What's Fire King? "Fire King" is a major brand of milk glass products, like Levi's for denim. At the time, various brands existed, such as Pyrex, Federal, and Glasbake, and they offered a variety of products. Fire King was born in 1941 during WWII, and the "heat-resistant glass that doesn't break in the oven" was revolutionary at the time. The affordable, sturdy, and easy-to-use Fire King products quickly became a staple on American tables and in restaurant ware. However, in 1986, the company transitioned to a new production system for heat-resistant glass that was also environmentally friendly, and the production of milk glass products, which were difficult to make with the old materials, was discontinued. Currently, there are Brazilian reproductions and Fire King Japan, which newly reproduces items from that time.