For optimum meter performance, use two disposable AAA alkaline batteries.
Gates’ 508C Sonic Tension Meter is designed to use two AAA alkaline batteries, rated for 1.5 volts each (3.0 volts combined). When used with new alkaline batteries, the estimated continuous use time is 10 hours. Using other battery types, such as lithium ion (Li-Ion) or nickel cadmium (NiCd), may reduce the meter run time.
Note: The information in this blog post also applies to the older 507C model.