Valve core tools are fairly simple tools. This one does work better than most due to the ratchet. In theory, it will keep you for over tightening the core. As others have mentioned, the rubber slips on the plastic handle. Glued mine, problem solved. Since I had to glue the handle, my rating should probably have been a 4 but all other core tools are insubstantial compared to this one.
Rating: [5 of 5 Stars!]