Professional 100 lap memory stopwatch.Water resistant and shock resistant caseRepeating Countdown/up timerPacerAlarm and time day date displayMeasures up to 9hrs 59mins 59 secs 99/100ths sec.Triple display shows: Cumulative and Lap split time to the last split. Cumulative running time.100 cumulative and split times can be stored in memory with fastest slowest and times identified.Time out (start stop resume) function is also included.Takes CR2032 battery (included)Batteries are dangerous if swallowed. Keep out of the reach of Children.;When changing a battery in a Fastime watch ensure that where there is a spring it is in the correct position (under the battery) where there is a clip to hold the battery ensure that the battery is in place under the clip making good contact with the elements. If the watch face still remains blank it may be that the watch needs re-setting this can be done by creating a 'U'-shaped tool from a paperclip and simultaneously touching one end to the back of the battery and the other end to the contact in the reset hole to the left of the battery bar screw.