Mystic Leg Strap Set
The Leg Straps set from Mystic are straps with velcro closure that wrap around your ankle on top of your wetsuit to ensure that no water enters through the bottom. (these straps come standard with your Mystic wetsuit).
You don't want to miss these straps during a kitesurf session. Also, wetsuit which is intended for wave surfing never have these straps but getting a pair is really useful.