The pot lights fit almost like a surface mount fixture, instead of a large metal can they just grip the ceiling drywall. Each light comes with AC to DC transformer and that acts as the junction box. These are the fixture we will be using just about everywhere in my next project. I am going to be building a project to be 'hardened' for leasing, so I don't want to be changing bulbs and cleaning dusty fixtures (or worse fixing damaged wall lights).
These are a plug and play item. Easy to install as well
The transformer gets the other end of the plug.