I use the gear wrench version of those, been using them for years and love them. Like 85 SS says, you can't put them under a lot of torque. They are also prone to jamming up from grease and grime that builds up in the gears, so you have to keep them as clean as possible. They are fantastic for getting into tight places where a regular socket and ratchet won't fit. If you treat them right and keep them clean I think they are one of the best tools you can have in your tool box. The gear wrench brand also has a lifetime warranty and can supposedly be returned to most sears locations but I've never tried.