R1800 Membrane Clamp Lockdown Clamps Home » Products » CounterLine Plumbing Products » Roof Drains » R1800 Membrane Clamp Lockdown Clamps MIFAB® R1800 cast metal membrane clamp lockdown clamps with 3/8” (9) hardware. Specification Sheet Catalog Catalog List Pricing Current Catalog: CLPB-2022 Return to Products