Shaatnez is proibition from the Tora of using a vest that contains wool and flax.
Only the Cohen Gadol could use when he was at the Beit Hamicdash at Jerusalem.
This a decree that is over our understanding. Although there is a interpretation that somehow explains;
- Caim and Abel took their offer to G-d. Caim was agriculturist and took plants that result on flax and Abel was shepheard that took his sheep that result in wool.
According to Cabala these two sons of Adam represented spiritual opposit powers that must be always separated as the offers (can’t be blended).
Take a look how to discover flax fiber.
Flax
is an natural fiber that comes from tha caulis.
Some caracteristics of this fiber are:
> Long, Smooth, Resistant and More bulky than cotton
> Brilliant, White
> You can “comb”, Undos easily
> If you fold the fiber, It breakes easily (because it’s from caulis and grows up- that’s why everything that comes from caulis kneades.)

Picture of Flax :)
Remember that need to burn the fiber, right?
> It lasts to burn, Makes some smoke and then it dies away and Makes ashes
> Smells like paper burning or wood
> The DIFERENCE of cotton is that flax does not continue burning!!