Our magnets are 16mm dia x 35.7mm from the magnetic face of the magnet to the top of the hook. You can put this hook on wherever there is a thick magnetic face, a 10mm thick plain iron ceiling for example, and it can hooks 5.5kgs, the power reduced by 2/3 when using it vertically. Please note that the magnetic power would affected by the surface, meterial and other factors, thank you.
!