This is a great tool for creating small bullseyes at the end of long cracks to isolate the damage and prevent them from extending. The Slide Hammer has a spring loaded snap shaft which, when pulled back and released, transfers the right amount of energy to the carbide tip making a perfect bullseye! Can also be used to open tight bullseye breaks that may be hard to fill. Or drill a small pilot hole in the damage or at the end of a crack, place the the carbide probe in the hole to create a small bullseye to be filled with resin and terminate damage.