Condenser tubes with additional flank structure

A metal heat exchanger tube (1) comprising a tube wall (2) and encompassing fins (3) on the tube outer side (21) which have a fin root (31), fin flanks (32) and a fin tip (33), wherein the fin root (31) essentially projects radially from the tube wall (2), the fins (3) tapering over their entire extent from the fin root (31) to the fin tip (33), the fin flanks (32) are provided with first material projections (41) which essentially extend in the axial and radial directions and adjoin second material projections (42) which essentially extend in the axial and circumferential directions of the tube (1), the first and second material projections (41, 42) having a common boundary line (43),

• characterized in that
• the axial extent of the first material projections (41) along the boundary line (43) is smaller than the axial extent of the second material projections (42), the first material projections (41) extend beyond the fin root (31) in the axial direction and each first material projection (41) adjoins not more than one second material projection (42).