A slide is supposed to be very simple; but this one has a couple of things that sets it apart from others. First, the finger rest on the side: it is indeed very useful and adds to stability as it allows you to support the slide, especially if you use slide in conjunction with normal playing. Second, the knuckle cutaway allows you to bend your finger without much resistance. Beware of your ring size and note that you may prefer to use this on another finger than the usual one due to its particularity. So, be prepared to order several sizes...