Chrome-plated cover plate includes slotted locking mechanism.,Opens with simple turn of a flathead screwdriver or coin.,Cover plate consists of 7"(18cm) O.D. chrome outer ring and hinge chrome cap.,Heavy-duty steel sleeve recieves 3" to 3.5" upright and is 9.25"(23cm) deep.,1"(2.5cm) clearance required between top of floor and sleeve.