Have used these before, and will keep using them.

good for what I am using them for.

I needed fasteners of some kind to secure the frost blankets I put over vulnerable plants and shrubs (including 2 fairly big palm trees) when winter freezes arrived. Clips/clamps are less expense and much less trouble (especially at take down time) than grommets, which sometimes aren't in quite the right locations anyway. So, I bought a small quantity of (a) "ProGrip 907040 Tarp Shark Cover Clips" (Sharks for short), and (b) "Presa 61000 Heavy Duty Tarp Clips" (Presa's for short) to test. Both are available from Amazon. I had already learned from experience that I wanted devices that would "screw" together to bring maximum holding pressure to bear and use some form of "teeth" to prevent slippage. Ordinary clamps and clips just don't stand up to winter winds. Before the first winter storm and feeze hit I deployed my usual 25 blankets that have grommets installed, but leaving two shrubs available to test the "Sharks" and "Presa's". Both devices performed well, blankets were still in place the next day. However, there were differences in 'ease of use'. It was noticeably easier to apply maximum tightness by twising the 'fin' on a Shark, than the knob on the 'Presa'. And, the mouth of Shark opens wider than that of the Presa, thus admitting bulkier (or more layers of) blankets. For these two reasons I gave the Sharks a five star rating (this review) and a four star rating to the Presa's (in a separte review). Then I promptly bought a bunch more Sharks and began phasing out the grommet - parachute cord applications. The worst of winter is now past (I hope) and I'm very pleased with the Sharks.

These work amazingly well, and I'm currently using them on both a motorcycle cover, and a four cord wood pile tarp cover.

The great thing is that you can just use ANY section on a tarp as an anchor point, and even synch-up loose flapping sections of tarps.

I've yet to see one of these Tarp Sharks loosen their grip once tightened.

I was in need of something to hold down my canvas type cover for my bass boat. The buckles that came stock on the cover always quickly break. These hold onto the outer edges of my boat cover very tight allowing me to really crank down on the ratchet straps that I use to go under my boat and trailer to hold my cover very tight! Shipping was fast as always and the item was described perfectly! Thanks for a great solution to my problem.