If you want to mount heavy pictures etc. this tool is a must have. /www.amazon.com/Zircon-StudSensor-Electronic-WireWarning-Detection/dp/B079PYX9NJ/ref=sr_1_13?dchild=1&keywords=electric+power+and+stud+finder&qid=1599141876&sr=8-13 This tool was designed for various purposes develops applications, but I've only used it on drywall. It also shows you if you have a chance of hitting the "power line" and helps you find the center of the wooden post. Hairpins - no, and start over, otherwise you will not be able to use the tool. This tool is for drywall only. It will also show you if you have a chance of hitting the "Power Line".