Electrical Test Instruments, LLC DBA ETI Precision (ETI) is a leader in the calibration and repair of test and measurement equipment, specializing in high-current and high-voltage instruments. We also manufacture industry-leading high-current circuit breaker testers and AC/DC variable power supplies that are deployed at testing companies and within critical environments worldwide. We provide nationwide onsite service, minimizing the downtime of your critical instruments by offering calibration services at your facility. ETI is also able to repair and retrofit a wide variety of test and measurement instruments. Our emergency onsite repair services are available for your urgent equipment issues.