Good protection for transport: box + bubble wrap. The description is not really exact : I bought these lamps for my kitchen extractor hood. The holes are already made, exactly for 50 mm diameter. The body of the spots is 50 millimeters, but they do not fit in because of the mounting springs and the side screws, the real gross diameter is 54 millimeters.
Easy to install, so far working great! hope it will last long...