Gasket for Nipple-Nut Kit. Installation of the nipple-nut kit on the polyethylene tank: Required parts: – Male thread nipple kit + nut + Female thread plug. – Gaskets for male thread connection (2 pcs.) – seals the inside and outside of the tank wall. – Gasket for female thread plug (1 pc.) – allows sealing if the plug is used to insulate the connection.