Googling brought nothing remotely useful
Just to join the line of people pointing out you need a 9V battery, I'd like to mention that fluke.com is a mine of information.
Which reminds me: when I was a mere youth, 9V batteries were generally piles: a stack of 6 little lozenges that left nasty marks on everything they touched. Nowadays, they tend to consist of six AAAA cells, and the cheapest way of buying such cells.