Both the senior and the S-shaped airlock sold standard with our fermenting jars serve the same purpose.
By putting water in the airlock and inserting it into the grommet on your fermenting jar, you are effectively creating a one way valve. The water in the airlock stops moulds and other contaminants from getting into your ferment whilst it allows CO2, a by-product of the fermentation process, to bubble out of the jar preventing it from overpressurising and potentially even exploding.
Some people find the senior airlock easier to clean and better suited to very active ferments which may draw the fermenting liquids into the airlock.
To use, Insert the airlock into the grommet (not too far as this can damage the grommet) remove the cap on the top of the airlock, fill with water, replace the cap and you are ready to go. The airlock should not require any further monitoring for most fermentation processes, provided there is always water in it.
