Symmetric spinnakers have the windward clew secured to a spinnaker pole. Sails include a jib, 150% genoa and a spinnaker. Main, mizzen and spinnaker booms are aluminum. Used when sailing downwind, it is a cross between a genoa and a spinnaker. The spinnaker and its halyard thus form a continuous loop, passing through the chute. The top of the sock will have provisions for attaching to the spinnaker halyard. Combed singles yarn sailcloth in high counts is used for spinnaker and head sails. It has greater camber than a genoa (but significantly less camber than a spinnaker). It was built to resemble the billowing spinnaker sail of a J-class yacht. Sail area for the spinnaker is maximum. The rig is a Bermudian rig sloop with spinnaker. Sail area is , the optional spinnaker is . Due to its geometry, the sail is less prone to collapsing than a spinnaker. Its name derives from the fact that it has the shape of a spinnaker (sail). The 420 has a bermuda rig and an optional spinnaker and trapeze.