I think doug went pin under ring.
I have two, one is pin under bridge, gave me a great midlane read, smooth when it changes direction and nice little pop on the back with the polished cover. Can be stronger than expected on shots with less head oil.
Second one is drilled pin under middle finger for more length, has a P4 weight hole, gets rid of any kind of under/over shot. Very good sport shot ball for me, worked well up the boards on Viper last weekend.