This is not waterproof rated, although the shell halves are designed to fit tightly together when closed. The instructions include a handy guide for strip lengths to help dress the wires properly in the plug. I had some issues wiring it since the receptacle pins aren't bonded in the plug shell, they just sit in recesses. You can pull them out to make wiring easier, but it's a bit of a chore to then push them home with the wire attached and dress them properly in the top shell.
The strain relief clamped tightly on the wire. Watch out when disassembling that you remember to remove the deeply recessed screw in the center of the plug - you'll need a skinny Robertson screwdriver to get it out.
The only con I have is the connections for the wires. The hold down screw is in the center of the clamp making it difficult to push the stranded wire around either side of it. An alternative is to spread the bare wire into 2 leads and push them on either side of the screw.
The pull handle makes it easier to separate the extension cord from the main RV cord - plus, the bright yellow color makes it much easier to avoid breaking it by running over it in the driveway or campsite.