A planning magnetic disc is a basic magnetic disc encased in ABS (Acrylonite Butadiene Stryene) plastic. The plastic casing covers two out of the three sides of the magnetic disc, leaving a single magnetic face free to stick to different ferromagnetic surfaces, for example a fridge door.
ABS plastic is colourful with an attractive smooth finish, which makes it ideal for making the case of a decorative fridge magnet. It is also very tough and rigid which protects the magnet from any wear and tear that could affect its magnetic capabilities.
Planning magnetic discs can be used on whiteboards for planning events by allowing different pieces of paper to be held onto a whiteboard in a colour coded system. This is where their name, planning magnetic discs, originates.