DOGYU Outer Wall Inspection Tool Pumpkin Ball Percussion Stick 1500 [Storage-Up To 270-1530mm] 01737Product code: 01737 Total weight: about 190g Ball diameter: 20mm atypical sphere Storage longest: about 270 1530mm Shaft: 9 stage telescopic stainless steel tube rubber clip JAN code: 4962819017371 Demonstrating power on concrete and mortar surfaces! The sphere is an atypical type reminiscent of a pumpkin. Diagnose the sound by rotating sound. I hear a loud sound. If there is a cavity near the concrete surface, the sound will change.