Quick take
Waterdrop currently lists G3-N3CB for up to 12 months or 1,100 gallons, at $29.99 one-time.
What G3-N3CB is
G3-N3CB is the carbon-block stage in the Waterdrop G3-family replacement set.
Published lifespan
Waterdrop rates it for up to 12 months or 1,100 gallons depending on water condition.
Current price
The current one-time price shown by Waterdrop is $29.99.
Pairing with the other cartridges
A G3P800 owner normally replaces the CF stage more often and the RO membrane less often, so filter alerts should be tracked by cartridge rather than replacing all three together.