These holding magnets with Alnico comes with a lifting handle. You can use this handle to lift with, aswell as using it as help to release the magnet from the surface. Either by tilting the handle, or screwing the handle down to the bottom, making it push away from the surface.
The stated forces have been determined at room temperature on a plate in polished steel (S235JR according to DIN 10 025) with a thickness of 10 mm (1kg ~ 10N). A maximum deviation of -10% compared to the specified value is possible in exceptional cases. Value is exceeded in general. Depending on the type of application (installation situation, temperatures, counter anchor etc.) the forces can be influenced enormously. The indicated values are serving as an orientation.