Amprobe GP-2A [4129187] Ground Resistance & Resistivity Tester*DISCONTINUED SEE AEMC 4630 KIT-150FT*. The Amprobe GP-2A Earth Ground Resistance Tester provides accurate and reliable measurements for ground resistance and soil resistivity to assure the safety and performance of an electrical system. Poor grounding is dangerous and contributes to unnecessary downtime and increases the risk of equipment failure. The GP2A ensures reliable installation and troubleshooting. The Amprobe GP-2A measures earth ground resistance with either 3-point or 2-pouint tests, calculates resistivity with 4-point tests and can store up to 999 measurements. The tester is complete with PC software that allows the user to download critical recorded measurements and to create professional reports for customers.