I purchased a kayalite from Kayalu about 6 months ago. The paddling group I'm a member of like to do early morning and moonlight paddles.
This light has great visibility and is simple to install on any kayak that has either bungee lines or eyelets for bungee lines. When attached to a bungee line it will not be quite as secure as attached to an eyelet, but the well thought out cord tightened clip will hold the light in place in most circumstances.
In short, I had to order another one for my wife's kayak. The light stands high enough to increase visibility even when it is behind you. I recommend it for anyone kayaking after dusk or before dawn.