Here is what Prodigy has to say about the M4:
 
The Prodigy Disc M4 is an extremely reliable understable midrange disc. It is designed for all players and flies extremely far for a midrange. The M4 will turn up when thrown hard and will then have an extra long glide and a soft straight finish.
 
AIR Spectrum is a line of premium, lightweight discs. They are engineered for the same shot performance of their heavier counterparts with added glide.