Using this for a Sunfish day sailer (13 foot) and it works perfectly. The elastic lower seam should snug tight around any of the dighy sailboats like the Laser, Sunfish, or Optimist. It is not the thickest cover (150D), but that's not always the measure of quality. I tend to look at this like a pair of shoes -- calculate the cost per wear. I've tried more expensive covers and I seem to get no more than one season in the harsh Cape Cod winter, regardless of purchase price. Therefore, why not go for the bargain? The cover comes with quick release webbing straps to hold it tight. I've found these are too small for the entire circumference of the sunfish. I use 2 on the bow and stern. The rest I guess are made to hold the elastic straps of a v-hull to the trailer, but I have no use for them. The elastic gathering seems enough to hold tight even when transporting on the highway. I use bungee netting over top for extra security. The cover is just large enough to cinch around the Sunfish using the splash guard to create a trampoline over the cockpit. That's my primary concern -- make sure the inside is tight and dry. I would imagine the reflective surface is probably good for shedding UV, but I am far enough north that this is of little concern except during summer.