To be used in conjunction with the 450mm Inspection Chamber Bases B5494 & B5696, this underground inspection chamber riser is 450mm diameter and 325mm in height. Risers are used for extending the chamber depth to your required size, you can stack them or they can be cut to the size you need which you can do with a standard fine-toothed saw. This riser can also be sealed with the use of the B5398 sealing ring. A typical 450mm chamber system can comprise of a chamber base, risers, ring seals, restrictor ring and a suitable cover & frame.