This is a sewer cover. I use it to cover my bathroom sewer. Because the sewer cover is always

blocked, I design the new one to improve the shortcomings of the original one.

the new cover can use the leaking holes on the curved surface to continue the flow into the

sewer when the bottom leaking tank is blocked. The original cover is completely flat. In this

way, when dirt blocks the leaking hole, there is no way to continue flow the water into the

sewer.