First number is the (drill?) angle. Basically the angle between the MB-pin and pin-axis. Larger angles put the MB closer to your thumb. Smaller angles closer to the VAL.
Middle number is the pin-to-pap distance. 3 3/8 is largest flare for most balls. Shorter gives you a smoother, lower flaring movement. Later will give you a later and more angular movement.
Last number is the angle to the VAL. Basically the height of the pin. Small angles means the pin is high up. Large angles put the pin further down. Hope that helps..
For visuals, google Morich Dual Angle layout.
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Penn State Mens Bowling