A spring interior comprising a plurality of longitudinally extending bands of springs disposed side by side and connected together by helical lacing wires in the top and bottom faces of the bands. Each band of springs comprises a single length of wire formed into a plurality of substantially vertical coil springs interconnected by interconnecting segments of wire located alternately in the top and bottom faces of the bands. The coil springs of each row are interconnected by interconnecting segments with the adjacent coils of the same row. The interconnecting segments comprise a planar bridging portion which extend generally lengthwise of the row and arcuate end sections which extend generally transversely of the row. The arcuate end sections are planar and connect the coil springs to the bridging portions of the interconnecting segments. The arcuate end sections are of approximately the same radius as the coil springs to which the arcuate end sections are connected.