Ducts of metal, for central heating installations; Junctions of metal for pipes; Metal expanding sleeves for affixing screws; Metal fasteners, namely, bolts, nails, rivets, screws; Metal fastening anchors; Nuts of metal; Pipes of metal including those from alloy steel and titanium; Pipes of metal, for central heating installations; Pipework of metal including those from alloy steel and titanium; Plugs of metal