To buy a demonstration chess board several factors play a role. For small groups the demonstration chess board should at least be 80 cm. For larger groups between 100 and 120 cm. The demonstration boards in the shop have several ways to be displayed. Either with a cord which works well in practice and a tripod for that is available also in the shop. Another way of attachment is with cords with a small ring. Metal sheet demonstration boards are heavier and often stand on a flip over display or hang on screws into the wall.
There are three kinds of demo chess boards, slotted, pocketed and magnetic. There is no significant difference between slotted and pocketed. Both do the job well. Slotted just means the pieces have tabs that slide into slots on the board. Pocketed demo boards are more common and the pieces are just little pictures that slide into clear pockets. The pieces with clear backing are easier to see. Magnetic demonstration chess boards are more elegant and are especially nice for demonstrations.