- The superior flexibility of the Tripost means it has greater resistance to bending and can penetrate even the harshest stony conditions. More information... A galvanised steel vineyard trellis post designed by vignerons for vignerons. The posts provide maximum resilience and wire retention. More information... A unique vineyard trellis system that is unparalled in vineyard development today.www.tristaroz.com.au/index.htm