This one-piece chamber base and riser forms a 250mm diameter mini inspection chamber with a level invert base. It is usually used in conjuction with our UCL2 circular PVC cover and frame.Level invert chambers are often used when the installer has little fall to play with on the pipe run, such as when connecting a new section of drainage to an existing pipe run. A standard mini access chamber has an integral fall from the side inlet to the base, and this can take up valuable height when trying to minimise the fall on the new pipe.The overall depth of the chamber from the invert level to the top of the manhole cover (when using the UCL2 cover) is 612mm. If you need to make adjustments to the height then the side riser may easily be cut to size using a standard fine-toothed saw.The main channel of the base is left open and the side inlets are blanked off with integral blanking plugs - simply remove the blanking plug by pushing it out from within the base to open and use the side inlets.