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 X-Line Plastic
High durability, excellent grip, even when wet, more consistent flights.