6" DuraVent DuraPlus Black Transition Anchor Plate 6DP-AP13X21 6" DuraPlus Black 13" x 21" Transition Anchor Plate is used with a Slip Connector and Hanger in chimney restoration to connect DuraLiner pipe to DuraTech DuraPlus or DuraTech Premium Chimney. Painted black. Diameter: 6" Dimensions: 13" x 31" Painted black .016†430 stainless steel outer wall or .018†galvanized steel outer wall. .018†aluminized steel intermediate liner. .016†430 stainless steel inner liner. Insulated layers plus ventilated air space. Locks tightly with a precision twist-lock connection.