Can the catches be fitted to metal posts?
They will fit any flat surface which can be drilled and bolted (10mm bolts or screws) on metal posts many people have welded them on to the upright, this can be done using mild steel filler rods or mig wire, this will give a weld that is quite rustproof (for many years) however if the post is galvanised it would be worth treating the weld with cold galvanise or an anti-corrosion paint such as Hammerite .
