Pool Nature 2 Express Cartridge - $85 (Southlake)

My stupidity is your gain! I ended up with a case of Nature2 Express cartridges as opposed to a single unit.
I am selling a few extra cartridges.
They are new, unopened, in the manufacturers original packaging.
They are $146 on Amazon.
I will accept $85 cash.
This is for the cartridge only, and does not include the housing.
Thank you.
Nature2 Mineral Dispenser The Nature2 Express by Zodiac is a mineral sanitizing system for inground and aboveground swimming pools that reduces the need for large amounts of chlorine.
As water flows through the Nature2 Express system, mineral ions are slowly and consistently released into the pool water, providing just the right amount of bacteria- and algae-fighting elements to keep your pool perfectly clean and fresh.
Nature2 Express is the most convenient and easy to install mineral sanitizing system.
In just minutes you can install Nature2 Express, activate the cartridge, and start enjoying all the pleasures of swimming in a mineral pool.
Features • A BETTER SWIMMING EXPERIENCE GUARANTEED • Reduces chlorine use up to 50%.
• Controls algae and bacteria.
• Decreases pool maintenance.