Tempered glass is a specialized type of safety glass. It’s created through a process that rapidly cools the material, which in turn creates increased strength. The level of strength varies, depending on certain factors including how quickly the material is cooled and its thickness. And unlike other types of glass, tempered glass breaks into small, pebble-like pellets rather than shards. This makes it ideal for shower doors and windows because if they break, you won’t cut your fingers or step on sharp edges or cracks.