Let’s start with the easy stuff. A belt is not a serious piece of powerlifting equipment. Velcro belts are often worn by professional strongmen UNDERNEATH their regular leather, powerbelts. That should tell you what you need to know about the kind of support they offer. They’re mostly useful for keeping the back warm, but they do not offer much in the way of added safety nor in the way in of lifting heavier weights. They can be nice to have around if your back is stiff and you want to do some work that a regular powerbelt would interfere with. Stone loading and the Olympic lifts are some potential examples.In my opinion, a double-pronged belt is completely unnecessary and often very, very annoying to use. The idea behind getting a double-pronged belt is that the extra prong more evenly distributes the stress on belt thus making the belt more unlikely to fail under heavy loads. This is actually true. However, I have NEVER seen a quality single prong belt fail under a load and I’ve seen multiply squatters handle 1000lbs+ in such belts. If you don’t buy a piece of junk, you have nothing to worry about. Long story short, single prong is fine and much, much easier to adjust from hole to hole than a double pronged beltNow, let’s talk about belt width. You should not get a belt that is tapered from the front to the back. The only exceptions to this rule have to do with geared bench pressing where the belt is primarily used to lock the shirt into place and conventional deadlifting where lifters sometimes want less coverage in front to prevent interference with their set-up. However, even if a belt is tapered, the maximum allowable width, AT ANY POINT, is 4″ in nearly all powerlifting federations.