Access chamber for cable/optical fibre duct installation. Designed with modular, stackable ring sections, each with a height of 150 mm, to build a chamber of any required height. Each ring has a double wall structure with vertical reinforcing and fastening ribs between the walls. Covers meet the the PN-EN 124 standard; available in classes B125 and D400. Available in a wide range of applied materials including composites, cast iron, steel and concrete filled reinforced steel.