Most people don't often need to drill a 4", 5" or 6" hole in anything, but it's nice to be able to do it when the time comes. That's why I picked up this kit. I'm a jack of all trades and avid DIY enthusiast, and by the time I'm 38 I could probably count on two hands the number of times I've had to drill a hole larger than 3" in diameter. If you can say the same thing, then it is this set is probably for you.If you drill a TON of large diameter holes you probably want to invest in a better set.Steel bits, especially large ones, seem a little flimsy.Also the depth of cut is only about 1" so it's only recommended for thinner ones Materials such as plywood or drywall are suitable The case is handy for storage and organization For what they are and for the price this is a good set of large hole saws PS- The in ande Ren reviews mentioned the smelly liquid is just an oil that coats drill bits to prevent rusting.