I use a survey master. The battery lasts, for me, longer than any other I’ve had. I bought a Delmhorst not long ago, but it froze up the 2nd day, so I traded for the Protimeter. I did not care for the size, shape, or display on the Delmhorst. Prior to this, I’ve used Extech units for years. I’ve found them unreliable. No bad for the $$, but the Delm, or Protimeter indicate to any other pro on the job, that you are a serious inspector.