M
Matt This jacket is a must have. I keep mine in my truck all seasons and use it a lot. Winter it gives you that extra warmth you need for the frosty kite sessions. Summer it is nice for the late session when you get cold coming off the water.
This jacket has a nice lining that really warms you up. They offset the zipper and put the harness hole in the jacket so you can wear it over your harness. They have added better drain holes in the hood so that the water will drain out of your hood after a water start.
The Ion Shelter is definitely the nicest and most functional wetsuit jacket on the market.