The inspection probes are used to help assess the depth of damage both internally and externally. The probes come apart for easy storage or can be lengthened for tall or deep cylinders. The set comes with two tips, one curved and one straight. The curved tip is used to assess damage on the interior side wall. The straight tip is used for the interior base and external assessments. They are manufactured from stainless steel so they wont corrode and they are easy to clean. A great addition and necessary tool for anyone inspecting cylinders.