Yes. Mesh size. A regular good mosquito net has meshes 1,6x1,6 mm and that is good for mosquitoes but for small bugs like “No-See-Ums”. For them the mesh needs to be 0,6x0,6 mm. This also shows in price. A large bed net can be found for “no money at all” but the meshes often are very large.
We always use net with good quality and small mesh for the smallest bugs.