Measure depths in tight spots and up to 22” deep with this Super versatile tool. Precision measuring instrument used to determine the depth of any shape that has a step, groove, or slot. Features: range: 0 to 22 inch (with included 6 extension Rods 1", 2", 3", 4", 5", 6") resolution: 0.0005 inch Super high precision dial indicator - twice the accuracy of regular indicators indicator gauge conforms to AGD standard and Federal accuracy specifications indicator can be mounted on center or side of base. Base Length: 4 inch includes 10 attachments (6 extension Rods and 4 feeler points) protective case included.