I remember before I have a friend from Mindanao, he also have dowsing rod like that , but the only difference, there is a bullet capsule at one end of each rod, he told me that they put something inside .. which is I don't know what it is. ..
We tried it in Cebu northern part for curiosity together with my bro, we are wondering that when we are facing each other holding this 4 rods in a suspected location it will moved by itself.. .
When we try to use Bionic 01 - Long range gold detector it seems it confirm that there is something in that area. . . But we didn't pursue to excavate those areas because of lot of factors. I should carefully study it 1st with do more test with other GPR or detectors. . .