Bought a set of these a couple of years ago.  The hot water handle on one of the sets began to be tight and then I noticed the rust.  Took it apart and there was apparently a leak at the top o-ring and it caused the handle to seize against the chrome base, and metal washer within the base rusted and expanded.  This caused the base to seize against the washer and it bonded to the main trunk.  Not a very good design to put material that will rust in an area that could be exposed to water.