Operating Temperature: 30-110 degrees Fahrenheit Accuracy: +/- . Max # of Shots Per String: 70 Max # of Strings in Memory: 50 Max # of Rounds per Minute: 1800 Competition Electronics has taken all the best parts of the Pocket Pro II design and added improvements to make the ProTimer among the best in value on the market. Now you can get more useful practice session information with a simple built-in user interface. Collect and review all your shot data right from the timer display with a 50 shot string memory and hit factor scoring calculation. Requires one 9volt alkaline or lithium battery for operation (not included).