I'm still a bit confused on the mesh sizes. I ordered a 200 and a 600. Maybe they mixed up the labels, but my 200 has larger holes than the 600. For mine the 200 is tight enough to hold medium to large sand, but not fine sand. The 600 is about as tight as a reusable coffee filter and holds anything that isn't goo. Makes very quick work of rinsing my black worms.
From everything I'm reading though 600 should be "course" and 200 should be "fine".