Hi @timathis, There is a Built-in dual lithium battery in test arms, that can last 10 hours at a stretch with a single full charge that takes about 2 hours to charge.
DT71 Mini Digital Smart Tweezers - LCR/ ESR Meter, Multimeter, SMD Tester with Built-in Micro Signal Generator: https://www.seeedstudio.com/Mini-Digital-Tweezers-DT71-p-4696.html