In the photo, the mesh to the right is the standard version, noted for elasticity in all directions to improve contouring to the roof profile.
The mesh on the left is used on metal panels where appearance and smoothness is most important, such as a roof outside a window. Rarely is this version used for "lumpy" areas, inside gutter work or other situations where elasticity is truly needed.
For more on "matters of mesh", see "the battle of the thin red line" article.
