Real SlowFeeding makes the horse feel better and makes the hay last for longer.
RB Std Low A
RB Std Low A has a mesh size of 3 cm = 1 1/4" that is recommended for soft hay. It is designed to cover a standard round bale from the top down. It fits tight on a 120cm = 4' round bale. This solution is only recommended when used together with plastic feed rings because if not there is a well-known issue with horses spending all their free time trying to get their heads in under the net.
The actual height of this net is 145 cm and the diameter is 170 cm just to make it easier to dress the bale. I recommend you not to consider this net for a bale larger than standard.