This is such a good series of videos. This is number two of five for test preparation for the EPA 608 refrigeration exam.. Instead of trying to condense it down into one hour or less, like the majority of institutions or organizations. They’re actually going extra mile to go in depth and detail into five separate videos. The last one was just over an hour long and this one is an hour long. This is the way education should be thorough, in-depth and exact.. Not a synopsis and partial information outtakes like other training videos