It can take advantage of even very subtle light for timing accurately.

The process of it recharging is: it get energy from light, no matter indoors or outdoors, then just converse the energy of light to electric energy-----counter-recharging resistant processing -----exceed-recharging resistant processing -----energy storage processing ------then drives it and timing.

As long as your watch is exposed to light, the power cell will continue to recharge the battery. When fully charged, the battery provides enough power to operate the watch for 1-6 months – even if the watch has been in darkness. If your watch loses power we recommend you place watch in daylight for a full 5-6 hours (direct sunlight is the strongest source of energy for recharging)

Su: Each in Blue Gift Box (10 cm×7.5 cm×6 cm )
N.W: 78 g G.W: 211 g
Packing : 43 cm×41.5 cm×33 cm (100 PCS/CNT)