Arduino NANO v3 chinese replica (on Atmega-168 chip)
7 segment 4 digit LED indicator with common anode, FYQ-5641BD-21 (red LEDs)
8 resistors that limiting current on LED segments, 330 Ohms, 0.25 watts
RTC Module GEEGROW with DS1307 chip (very basic, only RTC chip, quartz resonator, button battery, no additional memory chip)
5x7 cm single side prototyping board
usb phone charger as power supply
2 push buttons
1 on/off switch
Gainta G521G enclosure (92x66.5x28мм)
5m power cord

Optionally you may need:

Capasitor with well capacity if your charger has small capasitor on output
Fuse, to protect your device
DC/DC transformer if you have power supply that gives more than 5 volts or less than 4.5 volts (this will give additional surge protection if your power supply dies, this can happen after 3-5 years of uninterrupted work)

Additional Notes:

My RTC module is not very accurate due to bad quartz chrystal calibration, looks like it is not exactly 32768 Hz and clock runs faster than it should be, giving about 5-8 seconds runaway per day. So i have to implement time correction in software (temperature changes during day/month/year is not very big - about 10 degrees Celsius, so we can use software compensation without thermal compensation).