Postsaver Pro-Set Resin Foam Makes Installing Fence Posts a Breeze. Strong & Light. Our award-winning Pro-Set is a convenient alternative to using heavy concrete for setting fence posts, signs, and more. Conveniently packaged in a 1.35kg small bag, users simply need to shake the bag which mixes the two-compounds, pour the contents into the hole, Pro-Set hardens in 3 to 5 minutes with full load strength in 90 minutes. Pro-Set is lightweight 1 bag is equivalent to using 40kg or 2 bags of Postcrete or Concrete, No Heavy lifting or water is needed. Pro-Set expanding resin foam is a high-density compound that expands in the hole forcing itself into all voids in the soil creating incredible anchoring strength. It doesn't absorb water like postcrete or concrete and can be used on Wood, Steel, and Composite posts