Polypipe Underground Drain Shallow Access Chamber Base 320mm for 110mm Pipes is used to allow for easy inspection and maintenance of a drainage system. The base benefits from 2x45 degree side branch inlets for 170mm pipes with 2 blanking plugs if needed. It features a simple seal and snap cap system for strong and durable joints. Should be used in conjunction with UG436/UG502 covers and UG438 side riser if needed.