A fully-interlocked flexible steel conduit designed for high strength in tight-spot installations. This conduit is manufactured from a bright tin plated steel strip which is fully interlocked at the edges to produce a strong, yet flexible product. The interlock feature does not allow the conduit to unravel if twisted and permits the conduit to retain its shape when bent. This lightweight product is compatible with many set-screw and clamp type fittings. The bright appearance of the finished product lends itself to installations where the conduit may be visible after final assembly.