GM450 mesh has a raised surface finish. GM450 has the same weave and strand as Walkway but is from a thicker material. Consequently it is a slightly heavier product and a more suitable mesh for requirments where higher loadings than Walkway are needed.
The LWM (Long way mesh) is across the sheet while the SWL (Short way length) is along the length of the sheet. Thickness is the thickness of the sheet being used to cut the mesh from. The strand is the width of each slice.
For more specific detail about Gridmesh including loading specifications please follow this link to Gridmesh Technical.