I bought this as part of a recent order and figured I'd describe it for anyone who couldn't find much detail on the web. Shown below are the parts that come in the kit (x4). Cat's paw NOT included.
The strap (seems to be made by BoatBuckle specially for Hobie) has an over-center buckle and extends to a maximum (hook to eye) of exactly six feet when the handle is flipped to tighten the strap. The handle tightens the strap by about an inch after the length has been adjusted. The fixed end of the strap is sewn around an eye which has about a 30º bend in it (difficult to see in the picture). The bolt, washer and small nut are for fastening the fixed end to the trailer. The separate metal bracket gets fastened to the pylon bolt using the larger nut, which is thin so that it can replace the existing one whilst using the existing bolt.
Problems: 1) The provided hardware for mounting the fixed end to the trailer is not long enough to go through 2" box section; it is for a single thickness of metal only. Not a big deal, but 2" box section is pretty common for trailer crossbars which are what this is intended to be fastened to. The catalog photo shows it bolted to the roller assembly, but the instructions indicate that it should go farther inboard than that. 2) the special narrow pylon nut does not fit my boat. Older boats had 1/2" thread for pylon bolts, but since around 1995 they have been 3/8" SS Nylocs.
3) The bracket for mounting to the pylon is simply butt-ugly with sharp edges.
So, if I can't use any of the hardware, it comes down to paying $21 for each of those nice straps. Then you still have to buy climbing wall anchors for the pylons, longer bolts to mount the fixed ends to the trailer, and either buy longer pylon bolts or modify the existing nuts. Other than the straps themselves, you need to replace everything. This is not what I had in mind when I bought a kit.
A great DIY kit can be made by buying climbing wall anchors for the pylons and then buying your own BoatBuckle straps. eTrailer.com sells them.