What is the difference between hotfix and non hotfix crystals?

The main difference between hotfix and non-hotfix crystals is where they are used and how they're used.

Hotfix crystals come with an adhesive on the bottom side which activates through heat. These crystals can be ironed on garment accessories. 

Non hotfix crystals don't have the glue coating on the bottom and are often used on nail art, cases, phone decorations, etc.