Sometimes opening a structure to get invert measurments can be a pain. The vert rod can help with that. Simply extend the calibrated vert rod into the strucure level and read your measurment.
Recently a new method has been developed that enables one to collect redundant invert data at any angle by using a lightweight calibrated measurement rod.
The vert rod is a foursided calibrated measurement rod with each side of the rod calibrated to c