The polymer upper section is suitable for LW 400 chamber systems and is equipped with a clamping ring and a hanger for sludge buckets. Continuously height-adjustable by 440 mm. If installed in roads, parking areas and comparable hard-surfaced traffic areas for trucks (Class D), the upper section must be underlaid on site with an approx. 15 cm thick reinforced supporting slab with at least 0.80 x 0.80 m made of B35 concrete. The exact design of the concrete slab must be calculated structurally according to the circumstances on site. A standard formwork and reinforcement drawing can be provided.