A7-C3 Membrane Clamp for R1260 Roof Drains Home » Products » A7-C3 Membrane Clamp for R1260 Roof Drains MIFAB® A7-C3, 15″ diameter lacquered cast iron membrane clamp and dome receiver with integral gravel stop with weepholes on underside to drain water. Catalog Catalog List Pricing Current Catalog: MPB-2022 Return to Products