Fission is MVP’s lightweight plastic: a premium base with microbubbles evenly spread through the fill, so the disc weighs less without a visible change. It’s the MVP equivalent of Innova Blizzard, and it’s shared across MVP, Axiom, and Streamline.
Lightweight plastics are for lower arm speeds. The disc gets up to speed easier, which is the point. Four moulds are listed in it.
It costs stability in wind and a little durability against Neutron. Don’t expect it to fight a headwind.