According to their Web site, it produce smaller particles, which are supposed to penetrate better.
https://www.pari.com/us/products/nebulizers-cups-us/lc-star-reusable-nebulizer-us/

There are three different PRi nebulizing cups:
Pari sprint- blue plastic
Pari plus- clear plastic
Pari star - red plastic cup( I started using this because I found out that it produces the smallest med particles that are inhaled to the deepest of your lungs)