This strap is only minimal in it's assistance to help me carry my kayak.
I own a Wilderness Systems Tsunami 135 and my husband has a Wilderness Systems Tsunami 145. My kayak is a little easier to handle at 46 lbs with this strap then my husband's larger kayak at 56 lbs.
The idea of the strap is to balance the kayak on your hip while you walk. I find this very painful as the very heavy kayak digs into my hip bone while at the same time the strap digs into my shoulder (I have bruises to prove it). It does help with fatigue in my arms, but that is all the help I've found so far. I am 5'5" and I find that I have had to shorten the strap all the way to attempt to get the kayak high enough on my hip to keep from hurting so much. In doing so there isn't much space to squeeze my body between the strap and the kayak.
The other problem I am having with the strap is the padding that is attached to the hooks that cup the cock pit rim. I cannot seem to get the padding to stick. Without the padding the metal hooks slip up and down as you carry the kayak making it that much more difficult.
If you don't want to buy a wheel cart or you have a very short boat that isn't as heavy maybe this strap is for you. For me? I'll be spending the money on a nice set of wheels.