Alchemists have in all times tried to turn one substance into another without any luck.
Until now. Our mad scientists finally managed to turn sunlight into moonlight.
If you think about it, moonlight is just second-hand sunlight. With the Moon Jar you can achieve the same effect without the need for a costly and bulky orbiting satellite.
On a full charge the Moon Jar will glow for five hours. It requires direct sunlight to charge, so the time might decrease during bad weather or winter.
Put some meaning into the phrase, "I'll bring you the moon".