Abstract: A collapsible conduit includes an elongated sheet configured as a coil, the coil having a longitudinal axis, the elongated sheet having a first edge that includes a first hem and a second edge opposite the first edge and that includes a second hem, each hem including an overlapping portion that overlaps with the overlapping portion of the other hem, the first hem interlocked with the second hem to form an interlocking arrangement between the first and second edges, wherein the conduit is collapsible along the longitudinal axis between fully extended and collapsed positions, and wherein the overlapping portion of the each hem has an arcuate cross-section shape when the conduit is in both the fully extended and collapsed positions.