The Bio-Tensor (One Hand Rod / Dowsing Rod / Bobber) is a rod whose end is formed as a ring, wire spiral or ball. It is a modern version of the classical dowsing rod, pendulum or muscle testing, which was developed by Josef Oberbach (1908-2003).

It's an advantage over other testing methods like a pendulum or muscle testing. It is faster and lighter in responding and the tested person will not be stressed. The Bio-Tensor is used for the diagnosis, (according to the Bioplasma Theory) in order to prove heavy metals, allergies and “radiations”, the compatibility of food or “the need of medicines”.