Compare Quick view 18” X 1” Drain Test Plug/Stopper MSRP: £139.95 (Ex. VAT) MSRP: £167.94 (Inc. VAT) These drain test plugs or drain stoppers as they are also called consist of two steel plates with a rubber insert. As the central steel wing nut is tightened, the steel plates push together and force the rubber to expand, thus creating a water... Add to Cart Add to Cart