Abstract: To investigate the quality and nature of perforations in a downhole environment, a ‘pecking’ finger and depth measuring probe that can be axially and radially displaced enables the perforation to be located and its depth determined, through sequentially pecking around the wall lining. By swinging a pecking finger supporting a depth measuring probe tip and measuring the displacement of the finger, the edge and center of the hole can be determined with the largest displacement being when the tip is fully in the hole. The depth measuring probe is then deployed and the depth of the perforation established by an increase in the force required to push the probe and by the displacement of the pecking finger as it is pushed back by the reaction forces. Radially extendable clamps at the ends of the tool fix the tool with a surrounding bore.