This No.1900 timegrapher is a precise mechanical watches test instrument, it is used for multi-testing by watch manufacturers and watch technician. The frequency diagram of the watch can be displayed on the LCD screen. According to different watches, the instrument will automatically adjust the optimal signal level during the test. The instrument will automatically calculate the rate deviation, amplitude, be-at error, and display them by the data in real time; selects ±99.9s/d at item rate ranges for result display, which can make the accuracy of rate deviation up to 0.1s/d. For the conventional be-at, the instrument can automatically respond; for the special be-at, can manually selects. The sampling period can be selected by 2 seconds, 4 seconds, 6 seconds, 8 seconds, 12 seconds, 20 seconds, 30 seconds, 60 seconds, and the average value of corresponding period will be regarded as the precise value of the watch. Six kinds of testing positions can be adjusted, and the simulation sound can be played in the speaker or mute.