These steps are designed specifically for thin wall, plastic and steel manholes and should be fitted at the chamber manufacturer’s premises or on-site. The SS601 is a flat flange threaded step with nuts to work with flat walls. The SS611 version has an angle flange to work with curved walls. We supply it with variable angle washers to adapt to specific manhole diameters. We also offer a stainless steel version which is suitable for much thicker 100, 150 or 200mm manhole walls.