4+ contains 4 net layers creating 3 partitions for hay. The outer layers are in 35 mm = 1 3/8" mesh and the inner two in 30 mm = 1 3/16" mesh but if you want it the other way, just turn the net inside out.The hay in the outer two partitions are eaten through one layer of net from each side and the middle partition is eaten through two layers of nets from both sides. This make this model perfect for hanging between two pools in the paddock or being placed in a container (to keep the horses hooves away from the net) when you want to slow the eating down as much as possible.