This dual counter can keep count of switch closures on two separate channels. It is used (and included) with our rain gauge, but each of the two counters on the board can be used for anything that has a switch closure like a rain gauge, water meter, etc.
The dual counter has a battery which ensures that the count is kept even if power is removed from the counter. The battery should last for years. This device has screw terminals for connecting to your 1-wire network, and does not require external power but if you choose to supply power to it, it will require 5 volts DC regulated power.