The immovable solar rollers must be fastened on the ground with screws. Each of the solar rollers is equipped with 2 plastic handles and 3 pieces of aluminum telescopic axles.Elastic ropes are used to connect a bubble cover and the roller. One end of the elastic rope should be fixed in the grooves of the aluminum axles and connect the other end to bubble cover. Then turning the roller handle, the cover will be rolled onto the aluminum axles.