Tempered Glass is about four to five times stronger than regular class and is known for its safety. And, unlike regular glass, tempered glass fractures into small, relatively harmless pieces. This is possible because during the annealing process the glass is cooled down slowly, which makes the glass much stronger. As a result, tempered glass is used in those environments where human safety is an issue. Applications include side and rear windows in vehicles, entrance doors, shower and tub enclosures, racquetball courts, patio furniture, microwave ovens and skylights.