RectorSeal's SureSeal Plus is a waterless in-floor drain trap seal with an added check valve to protect against property-damaging water backups. It offers 2”- and 3”-diameter sizes to accommodate most commercial and residential floor drains. Its sturdy EPDM, water-blocking check valve flapper and housing is designed to withstand up to 5' of head pressure. It also uses first-generation waterless trap seal technology to block toxic sewer gas and insects from infiltrating occupied areas.