Spin angular momentum of a photon corresponds to a polarisation degree of freedom of lights. and such that various polarisation properties are coming from macroscopic manifestation of quantum-mechanical properties of lights. An orbital degree of freedom of lights is also manipulated to form a vortex of lights with orbital angular momentum. which is also quantised. https://www.roneverhart.com/Mizuno-Prospect-GXC105-Youth-Catcher-s-Mitt/