When you need an absolute precision in X,Y and Z we suggest this frost resistant geodesic monument. The center portion will be anchored at 2,35m below the surface where the frost won't go. The protective shell, totally independant from the center section will be the one moving with the frost. A polyethylene cap will offer the space to put a reference number on the field.
For those area where a longer pipe can be easily installed. It shows the same characteristics than the TT2235 model with optional one meter extension.