Very Useful
When I found that my brand-name filtering water pitcher was delivering filtered water that just didn't taste good to me I added one of these activated charcoal pieces and tasted a significant improvement.  Tiny charcoal particles sometimes do flake off into the water - the don't bother me, but if they did I'd use my Finum tea strainer with it's extra-fine mesh to filter them out, or a paper coffee filter. I'll be setting reminders to boil the sticks per directions at regular intervals since I'm sure I'll forget otherwise.  These work well for me, better than just the filters in my pitcher alone.
Rating: 4 stars