I bought one of these to try it out. Loved it enough to buy 1 for each tool bag and 1 for the garage. Durable and easy to use. Might be a little difficult to see in a tool bag in the dark though. I'd still buy it again.
They are small but weighty as it is made of metal, good quality and should last a long time, if you dont lose it. I painted mine silver straight away as help with this. Improvements could be painted silver and a hole at the top for a lanyard/ piece of string making it easier to find in your tool box.
...or at least something like it. I like the valve caps that have the core remover built in, but I keep these things all over. 1 in the truck, one in the toolbox, one in the race toolbox, and one by the tire changer.