I believe NPT stands for Non-Particle Technology. Will act like a particle ball but without the particles, thus the arcing reaction of the ball.
Edited to add:
And from the Visionary website on the data sheet, it is a 1000 grit polished ball.
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I am the Sgt Schultz of bowling.
"I know nothing! I see nothing! NOTHING!"
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BR FAQEdited on 11/29/2008 10:21 AM