Aggressive 3-piece urethane from the late 80's.  Not bad if you have softer speed and/or a lot of hand.   Also, if I remember correctly, this one was easier to polish up than the Blue Angle.

It was a great ball in its day. I had the yellow angle, which was more aggressive than the original black one, but it picked up every speck of grease and dirt making it look like something out of a dumpster. The purple was equally aggressive, but did not get all gunked up. Worked well sanded or polished. The purple was one of the few balls i always wanted, but never got.