Three-piece (or "open-throat") boots were first developed by Mel Dalebout (around 1969), who introduced a rigid magnesium boot shell in that year (Brixia did the same thing with their aluminum shell at around the same time). The big advantage was that the main shell was a single piece that was convex at all points, meaning it could be easily produced using a plug mould. Conventional boots with overlapping flaps required more complex moulding processes. Engineers at Henke, Heierling, Sanmarco and Caber saw the advantage for high-speed moulding, and plastic three-piece boots were on the market by 1972, when Roland Collombin won the Olympic downhill in the Henke Strato.