PEX is an abbreviation for cross-linked polyethylene. PEX is usually used in tubing especially for the water system for residential and commercial purposes. PEX became popular because it is flexible and can be bent easily without breaking. Because of this, PEX tubes can easily transported without the need for it be cut into pieces just to fit inside containers. Also, PEX' flexibility means that it does not need any joints unlike metal and PVC pipes.
Crimping is a process of joining two pieces of metal or tubing by deforming one of the metals being joined like when joining a cartridge to the bullet. Another form of crimping is used in crimping PEX tubing wherein a metallic tube is used to join two PEX tubes.
Crimping PEX is very easy to do and the best way of joining two PEX tubes.