For those that don't know, JIS just stands for Japanese Industrial Standard and they are a slightly different size of Phlips screw driver. I have a set but they were a gift. I don't feel they are really a needed item, I went for a lot of years without them. If you know how a philps driver is made you will understand that philps drivers vary a lot from manufacture to manufacture and the same holds true with JIS. If you must own a set then by all means buy them, mine do fit better then the ones I bought at sears but not enough to worry about. I do have several sets of long handled ball drivers too, some I bought at Sears and I like them and I also have sets from other places like Tower, they are good too.