Erva Copper Bird Bath Purification Disk – Made in USA

These copper disks work great. I bought 2 and tried them out. I have a heated water dish outside for the cat colony plus a regular dish [not heated] so these 2 water dishes each have a disk and just as advertised the water in both stays nice and clean and free from slimey algae etc. I bought 2 more in case I add more dishes. Before these every so often I would have to scrub these dishes with power scrub that has bleach in it. They would only stay clean for a short while. When it rained in these dishes they would get green and slimey almost immediately. Since the copper disks no green slime and less mess. They are worth the money for me and I think the cats like the taste it makes the water.