In all the photos the adjustable mount is set to its maximum length and the panel is a small example size. Each magnet has a rated pull of 50kg and should be suitable for large panels.
Each magnet is 40mm in diameter and raises the mount about 28mm off the roof, with the flexible rubber section adjusting to suit the roof profile.
For use on steel surfaces only.
The magnets are neodymium but have a zinc coating which offers better corrosion resistance. Some boats in the marina have had these mounts for several years now and none are showing any signs of corrosion.
For reference, the fittings either side of the rubber piece are galvanised, the black plastic bit is nylon, and the nut and washer are A2 stainless steel.