Torx Security Bits are one of those items you rarely need, but when you need them, you need them! I had a set that worked fine but they were just under 1 inch long. So when I needed to get to a screw buried in a hole or casing, the ones I had just didn't work; especially if the hole is smaller. They work very well as their slim 3 inch diameter and length allow access to where they need to be. The fact that they are torx-proof means you can use them with regular torx screws as well as torx-proof screws. They have very good grip and bite on the screw and are nothing like the cheap chrome bit sets you find in discount carts. I only need them 1-2 times a month for my work so I can't give you a proper overview of the durability but I've used the tools almost daily for decades and they seem to be very well made. I have had no problems with them and would buy them again in a heartbeat.