the DD ones are great, top notch, but can be a little pricey. They were the first I bought, however I thought about it, and for what it is (just a plastic sheet essentially) you can buy VERY cheap ones on amazon, 3.5x3 etc for about 10 quid or something, i have two from amazon and they have lasted me a year, with no problems and are still going strong. They come with metal eyelets as well, so I'd advise that, you may have to replace them once every couple of years (if that!) depending on how frequently used. But for the price, its a no brainer for me!