The concrete oplanger is typically around two to three meters long and has a steel cylinder on the bottom. This cylinder can be placed on top of the wooden foundation pile, and rammed in to its wood to create a decent connection. The top of the extender are typically crushed to make a concrete connection with the floor, but there are dry connections possible as well. The length of the extender depends on the depth of the lowest ground water level, as the wooden foundation pile needs to be submerged in water continuously.