Here is the North description of their sails:

• North AP
  All purpose hard cloth mainsail. Great for lighter skippers in all conditions and for larger single-handed skippers in bigger winds. (Cigar window shape)
• North ZAP
  Same sail as the AP on the cutting floor but with a mid-section built of softer cloth. This sails flying shape becomes a click fuller than the AP when the breeze is up. Again, great for lighter skippers and for larger single-handed skippers in bigger winds. This sail may be a little quicker than the AP in 0-5mph wind conditions. (Cigar window shape)
• North Masters
  This design is also like the AP in that hard cloth is used throughout the sail. A fuller and little more powerful sail than the AP and ZAP . Straighter leech profile exit than the twisty AP and ZAP mainsails. Great sail for big water lakes and all weights of sailors. (Wedge window shape)
• North ZMax
  The same design as our Masters mainsail on the cutting floor. The difference being this sail like the ZAP has a soft mid-section. The sail's flying shape is a little fuller than our Masters. This sail may be a little quicker in 0-5 conditions than the North Masters. (Wedge window shape)