I can't tell from the pictures if it's steel or fiberglass. Spring steel would definitely be best. The diameter seems a bit fat, meaning that it will require a little extra effort to push into the ground. Sure, you'll know when you hit something, but those grips are gonna dampen the subtle sound differences that you need to hear when passing through different soils, etc. A good probe is going to transfer whatever the tip is encountering from the tip up through the shaft and out the handle to your ears as it is pushed through the earth. Good luck with it, man and be sure to let us know what you find!