True RMS sensing Built-in circuit will retain memory in case of power loss. Start switch has a safety feature which prevents loss of previously recorded data. Based on measurement frequency between 40-400 Hz. You may not have to climb a mountain to get the job done, but whether you work indoors or outdoors, the DM-IITM gives you peak performance in any environment. Data can be viewed in the field via its large self-contained backlit LCD display or can be accessed and downloaded through a personal computer.
Battery backup protects memory if a power failure occurs and allows recording session to continue.
The ACF-3000 is an optional accessory. A total of three would be required for a 3 measurement. Adaptor ACF-5 is required. Total of 600K RAM memory. The recording session length depends on the recording rate, the number of selections, recording mode, and recording interval.