Monarch Silver Ion Cartridge
Monarch Silver Ion cartridge from Watkins Manufactering, Lasts between 3 and 4 months, Designed to work in any hot tub
This "mineral sanitizer" introduces silver ions into the spa water, inhibiting bacterial growth. It is designed to fit in any spa, either inside the filter or suspended on the outside of it using part 76309 or 76310. This continuous silver ionizer cartridge will charge the water one time and that "charged" water will last for four months. Two year shelf life when kept in a dry place.