The Spin is an understable putter that is designed to glide somewhat longer than many other putters. It can be used both for putting and for throwing, where flight characteristics are reducedin both cases will help to find a little extra distance at low power.
In R2 Neutron plastic, you get a disc in MVP's recycled plastic line. R2 Neutron has been developed with the aim that both durability and feel of the plastic must be the same as their premium plastic Neutron.