The ideal solution for e.g. swimming ponds! Due to the strong rim there is a low risk when someone stands on top of the lid. The weight is distributed along the ring that rests on the bottom of a standard bottom drain. Very easy to insert/remove (for maintenance) with a koinet handle. Material: PE & stainless steel. Lid: Ã?35cm x 1cm, bottom ring: Ã?21cm x 2 cm. Total height: 20 cm. NOTE: comes in separate parts, due to shipping size. Easy to assemble.