3 in Dome Floor Sink Guardian Drain Lock™ BUILD-UPTamperproof Locking Mechanism Secures Grates And Strainers From Unauthorized Removal. Reduces Solid Waste From Entering Drains And Prevents Clogs, Floating Rags Or Bags From Blocking The Pipe Exit, Blocking In Common Areas Or City Main Lines, And Cabling That Damaged P Traps. Dome Shape Allows Water To Flow Even With Debris Build Up In The Sink.