From wrx-
http://www.golfwrx.com/270011/bridgestone-j715-460-driver/
You know when it’s raining and your driver face gets wet, and you can feel the ball slip off the face and go astray? On most driver faces on the market today, this happens when it’s dry, too. When the ball slips around on the face during impact, it causes unwanted spin and amplifies the effect of off-center strikes.
Bridgestone’s power-milled face (see it magnified above) is said to reduce that unwanted slippage at impact by adding friction, which enhances the quality of compression while the ball is on the face and reduces spin by 200-to-300 rpm’s, according to Bridgestone’s robot testing.
