This inspection chamber base has a diameter of 450mm and features a main channel of 160mm, an additional two 160mm inlets at 90 degrees and another two 110mm inlets at 45 degrees._x000D_Our inspection chambers allow access to drain and sewer systems for testing, inspection, maintenance and cleaning. These actions can be performed from the surface and should not require entrance into the chamber itself._x000D_KEY FEATURES andamp; BENEFITS OF THIS PRODUCT_x000D__x000D_Quick and simple installation_x000D_Arrives factory assembled in one piece_x000D_Design life of 60 years_x000D_Lightweight and requires no specialist equipment to lift_x000D__x000D_Compatible with most UK twinwall pipe systems_x000D_Granular backfill_x000D_Complies with EN 13598-2 (2009), SfA7 and Building Regulations Part H1_x000D_4 x 160mm inlets_x000D_2 x 110mm inlets_x000D__x000D_To view Turtleand#039;s installation guide for twinwall inspection chambers,andnbsp;click here.