The MR08 Hammer and Wall Cavity Probe Combo is ideal for both hammer probe and wall cavity applications. The hammer probe has an additional handle on the bottom to add convenience for angled, horizontal, and inverted hammer-probing needs. The bottom handle can be unscrewed and used as a wall cavity probe to measure the moisture level of insulation within the wall cavity and can also reach the inside face of the exterior wall. You can also install the impact plate for use with a hammer to punch the extended pins through drywall.