This Tristar Tester is supposed to help diagnose charging issues on iPhones that may be caused by a failed or failing Tristar IC. In this video I'll demonstrate how to use it for measuring resistance with a variety of iDevices. Once we use this more in field I'll post a follow up video. Tristar testers are here: http://gocellphonerepair.com/tristar-testers-are-here/ and here: Tristar Tester https://ebay.to/2GIEyK8 (affiliate) Fluke 15B+ Digital Multimeter http://ebay.to/2j9zXXF (affiliate)