Tempered glass is five times more resistant to impacts than ordinary glass. It is intended for specific applications:

• glass doors
• showers

Tempered glass is also used in more common areas:

• worktops, shelves, desks
• double window glass ...

This can also be combined with laminated glass (safety glass), to then build tempered-laminated glass (ex. railing).

The glass must first be shaped (cut, ground, pierced, etc.) before it is worked, which involves significant heating, followed by quick cooling in a wind tunnel. These steps create "tension" in the glass, which makes it more resistant to impact, heat, and tightening.