Discraft says this about the Soft APX: Discraft Stability Rating: X-Line 0.0
Note: The APX is more firm in the Jawbreaker and ESP Fundraiser plastic than the X-Line plastic
The APX rocks! Designed with a special elite plastic that allows for consistent release on crucial putts, it's just tacky enough for perfect grip, and sticky enough to grab the chains. It's perfectly stable too, so let 'er rip on short drives!
About Jawbreaker Plastic
Jawbreaker plastic was developed to be the finest plastic blend available for putt and approach discs. Super tacky - give 'em a squeak! Unique jawbreaker marbling. Advanced polymers provide good durability. Discs have a medium stiffness.