Geosynchronometer is a device that can put out a sun (or moon).
But it only works if it's charged with enough Woo Foo power, which is the reason why Brother Herman failed to activate it.
Then, Night Master takes it and kidnaps Master Yo to drain his power and transfer it to the Geosynchronometer. However, this plan also didn't worked after Yin defeated the Night Master with Toilet Brush of Illumination. Geosynchronometer is one of the weapons at the Woo Foo armory.