Drain Stopper, Includes Strainer Body, Material Brass, Plastic, Color Silver, Product Type Drain Stopper, Overall Diameter 2 in, Finish Chrome, Application Tub, Drain Stopper Type Lift and Turn, Fits Maximum Drain Size 2 7/8 in This tub closer features chrome-plated brass construction. It is designed for bathtub, sink, and shower drains.
They are heavy little drain covers of very good quality. Must be a metal or brass base I would guess. Simply cement them down and it beats unscrewing the old drain and hoping a new one threads in straight. Its fast and easy as well.