Water filter cartridge replacement.
These are cartridges for a Puretec WH2-30 whole house water filter. The one on the left no doubt in 12 months will look like the one on the right. The dark brown colour is a mixture of Manganese and Iron. The other filter not pictured is a carbon filter which removes the taste of Chlorine.
Generally these systems are set up in the garage where the water supply enters the house. Older properties may not have this facility, however, they can be set up outside on the incoming water supply. It is recommended to cover an outside set up to prevent the effects of UV rays and protect from frost.
If your looking to extend the life of your plumbing components and want to get rid of the Chlorine taste, this is the perfect solution. Meeting your plumbing needs.