If you are interested in dating them, I can give a few hints. North Bros. created Yankee screwdrivers, usually brass with chrome plate. During WWII, they were steel and painted black. Some time after WWII, Stanley bought them out and eventually they were just Stanley Yankees. There was a recall of some sort for awhile, and the spring was disabled on some, that were brought in. The spring fed shank is kinda dangerous if you're not ready for it. Since it was Stanley they made tools in the UK too, so it will depend on what is stamped on the barrel of your screwdrivers. I have a set, and they get used. Great tools, great price.