Specification - F1100-C-N - Floor Drain with Tractor Grate for Membrane Floor Areas MIFAB series F1100-C-N7 - lacquered cast iron floor drain with anchor flange, cast iron clamp ring with primary and secondary weepholes for waterproofing membrane and 7" (175) satin finished nickel bronze tractor grate. (For non membrane floors, use MIFAB F1100-N series). MIFAB series F1100-C-N9 - lacquered cast iron floor drain with anchor flange, cast iron clamp ring with primary and secondary weepholes for waterproofing membrane and 9" (225) satin finished nickel bronze tractor grate. (For non membrane floors, use MIFAB F1100-N series).