Features: Stainless steel telescopic design with reinforced pressure groove make it a firm and durable product. Sponge handle makes it portable, comfortable and shockproof. It can be freely telescopic to easily detect the wall. Easy to use, gently tap the wall to determine the scope of the cavity wall. It can be also used for tour guides, blackboard presentations and operational instructions. Specification: Material: stainless steelFull length: 100cm/39.4in, folded length: 22cm/8.7inRod diameter: 14mm/0.6inBall diameter: 19mm/0.7in Weight: Approx.85g/3oz Package list: 1 x Sound Detection Hammer