Used for measuring and checking screw threads, the micrometer has interchangeable anvils that match the screw pitch. It’s a somewhat easier-to-use alternative to thread wires, although it helps to have a standard to compare the readings against. I used one yesterday to analyze the wear on a customer’s milling machine screw. It was much quicker than the wires would have been. Amazon (Small Parts actually, and the price is the same there) has the Mitutoyo 126-803 Thread Micrometer for $67.75.
What is unclear is whether the micrometer comes with all of the anvils — without them the mic is useless and the product description is incredibly vague. Also, this may be an older mic as the Mitutoyo website doesn’t list this as a part number for their current thread mics. So, as with all deals, it’s best to check before ordering. Alexandria General Supply also lists this mic for a few bucks less with even fewer details, so the pricing probably does reflect that this is indeed a closeout of some sort.