These Countertop Water Filter Systems are good quality and use various standard size water filter cartridges which are widely available making the replacement cartridges lower in cost. These systems have a 3 year warranty.
Systems are supplied with a reliable diverter to attach to the areator thread on the end of your spout or tap. There are various filters available for these models with treatment varying from straight forward chemical treatment right through to cartridges that not only do chemical treatment such as chlorine, pesticides and herbicides but also heavy metals and many are also rated to remove cysts such as Cryptosporidium & Giardia.
These systems take a standard size carbon cartridge so they will always be cheap to replace the cartridges as they are available just about anywhere but we are cheaper than almost all.