The Farmi coiler roller has a diameter of 1 5/8", it is therefore alot easier to pull the cable out, as it does not need to bend as sharply and eventual kinks in the cable will slide past the roller. The Wallenstein roller, on the right, is 3/4" in diameter. It is a piece of pipe, and kinks on the cable are likely to get hooked behind the roller, thus preventing the cable from spooling out.