The F105W-1A has a 1/100 second stopwatch with a capacity of up to 59'59.99" and measuring modes of net time, split time, and 1st and 2nd place times. There are the options of an hourly time beep and a single daily alarm. It has an automatic calendar, although auto-adjustment for leap years is not supported as the watch does not record the year. The watch displays the text "ILLUMINATOR™" on the face above the LCD. This electroluminescent backlight assists with LCD viewing in low-light or no-light conditions. The watch is claimed to be accurate to ±30 seconds per month.
The watch is powered by a single CR2016 lithium button cell, which Casio claims will last approximately seven years (assuming 20 seconds of alarm and one second of light usage per day). The watch case measures 37.5 × 33.5 × 9.5 mm and weighs 27 g. The manufacturer's module number for this model (stamped on the stainless steel rear of the watch case) is 1572. The watch front is marked WATER RESIST. The instructions state that water resistance is limited to splashes, rain, and that the watch should not be worn whilst swimming.
The watch is controlled by three side push-buttons. The upper left button turns on the backlight, cancels the alarm, and is used for selecting settings. The lower left button cycles the modes of the watch: → Alarm → Chronograph → Time adjustment and back to the normal time display. The button on the right is the function button: when used after pressing the lower left mode button it starts and stops the stopwatch, or changes the settings currently being adjusted; but when pressed alone switches between the 12 and 24 hour modes.
The time or date is adjusted by pressing the lower left button three times to bring the watch to time adjustment mode. This causes the seconds to flash on the display. The top left button is pressed to cycle through seconds, hours, minutes, month, date, day, and normal mode. The right button is then pressed to adjust the flashing value displayed. When the adjustments are finished, the bottom left button is pressed repeatedly until the watch returns to normal mode.
The watch's display shows the day of the week, day of the month, hour, minute, seconds, and the signs for PM (or 24-hour clock), alarm signal, and hourly signal (double beep on the hour).
In stopwatch mode, minutes, seconds and hundredths of a second are shown.
- "F105W-1A Classic Timepiece". Casio. Retrieved June 12, 2011.