DESIGN FEATURESUpdated a year ago

BATTENS
Made out of glass- or carbon fiber either as solid version with smaller diameter (= stronger) or tube version with larger diameter (= stiffer). For a better understanding the mast is like the backbone of your sail whereas the battens act like the ribs of your sail keeping the profile in place. Same as the mast also the battens have individual profiles (thinner tip, thicker tail) matching the profile of the sail.
Simple rule: the more battens the more stable (= faster + bigger wind range) the sail becomes. But also the heavier the sail becomes as battens account for approx. 40% of the sails total weight. Therefore handling/wave-oriented sails usually come with 4-5 battens whereas performance oriented sails usually come with 6-7 battens.
As a second guideline smaller sail sizes require fewer battens than larger sizes.

CAMBERS
Usually there is a certain gap between the batten tip and the mast. This is necessary so that the batten can shift from one side of the mast to the other when sailing back and forth. A camber can be seen as a kind of connection between the batten tip and the mast filling out this gap.
This leads to much better aerodynamics as the cam enables a smooth transition between the thick mast into the thin sail body. In addition since the cam is braced against the mast the batten stabilises the sails profile much more effectively (sail becomes more stable = faster).
The downside is that the rotation from one side to the other becomes much harder. Plus the cambers need a certain space which requires a wider mast sleeve. This makes (water)starting much harder as the wider mast sleeve absorbs more water. Therefore cambers are mainly used on performance Freeride or high-performance Slalom sails.

FOOT ROACH
A sail with a lot of foot roach reduces the gap between the sail and the board (close the gap) which makes it more efficient/performance-oriented.
On the other hand a high cut foot with less foot roach improves the handling especially for all kind of ducking moves. 

PROFILE DEPTH
A deeper sail profile gives you more power and performance in general.
A flatter profile on the other hand improves the handling as the distance of the flat profile is much shorter when shifting from one side to the other.

BOOM- AND LUFF LENGTH
Together with the sail size all dimensions increase. Means in general the larger the sail the longer the boom- and luff lengths become.