Welded mesh fence (also 'weldmesh') uses pre-fabricated panels of horizontal and vertical steel wires welded into a rigid grid, fixed to steel posts. The mesh aperture varies: 50x200 mm is the standard 'medium security' panel, 12.5x75 mm is the high-security 'anti-climb' panel.
Galvanised welded mesh is widely used for schools, sports fields, builder's hoardings, and animal-yard fencing. PVC-coated welded mesh adds colour and another layer of corrosion protection.
For security applications, the post spacing and the panel-to-post fixings matter as much as the mesh itself. Standard fixings are clips or torx-drive security screws that resist hand removal. The post spacing is usually 2.5 to 3.0 m for residential and 3.0 m for commercial.