Metal hose is mainly refers to a spiral bellows; the other is a ring bellows.
Helical bellows are corrugated helix-shaped tubular housings with a helix angle between adjacent two corrugations, all of which are connected by a helix.
Annular bellows is a bellows closed tubular casing, the wave between the ring by the ripple in series. Ring bellows seamless pipe or welded pipe processing and forming. Constrained by the processing method, compared to the spiral bellows, the single tube length is usually shorter. Annular bellows has the advantage of good elasticity and low stiffness.