Players have always used some form of head protection over the years, from full-backs to loose head props.
But since the game turned professional in 1995, there are now strict laws about using protective equipment on the pitch.
And since October 2000, the International Rugby Board (IRB), the game's governing body, must approve any form of head protection.
Headgear is usually made from light plastic materials capable of taking serious impact.
They're often used by front row forwards to prevent blows to the head and damage to their ears while in scrums or mauls.
The most important thing to remember if you want to wear head protection is to make sure it is comfortable - otherwise it will cause unwanted pain and injury.
If you are a front row forward, make sure the cap does not cause you any problems in the scrum.
If you can, scrum down with a friend when you are trying on different models, to make sure it fits properly.