Clark Drain Manhole Cover Circular CD452 450mm (D) PolypropyleneThe Clark Drain Circular Manhole Cover CD452 has a solid top cover with slip resistant surface tread pattern. The cover and frame are manufactured from recycled Polypropylene and is dual locking (frame locks to chamber). It fits all major manufacturer's PPIC shallow inspection chambers and is ideal for use on tarmac, grass or gravel areas Compatible with CD499 reducer to restrict access into deep chambers as per part H of the building regulations.