The Delmhorst 2497/A-100/24 Replacement Uninsulated Contact Pins feature pin retainers and are for replacement use with the user's 2-E/4-E Electrode or 2000 Series Meter to extend the service life of the tool. These pins are designed for use on wood, concrete, and gypsum up to 1-1/2 inches thick and can penetrate up to 5/16 inches.