I have been a professional machinist for 2 years. Within that time, I was programming and operating a cnc mill, most all of my measuring could be done with a caliper. Now I have transferred to a cnc lathe, on a lathe I am expected to hold tolerances within .ooo5 or greater. Thus I needed to invest in a set of micrometers, but I didn't want to spend a lot of money. I found this set and decided to give them a try, even though I was worried the quality would be sub par. Typically, cheap micrometers are made in china or Taiwan. I was very impressed when they arrived, the storage case was well built, each micrometer was individually sealed in plastic with a oxygen eater inside, as were the standards. The thimble on these mics move really smooth, but not so smooth that they move for no reason, the ratchets have a good feel too. The mics are very well balanced so I don't have figh.t with them when ever I have to measure away from the lathe chuck. The standards that the kit comes with are dead on, I compared them to the standards that the company I work for has, which are Brown and Sharpe, and they were exactly the same. I have been using these mics for about a month and a half and I can assure you I have tested them adequately, throughout using these mics I noticed there is a slight variance, I would say they vary about 50 millionths of an inch, so if you don't have to measure that small I would consider them to be a very good value.