Introducing our new Breakthrough Indicator Stickers for low-flow and manhole filters. As the carbon in your filter becomes saturated, the Breakthrough Indicator will turn from green to brown to black, letting you know to change the carbon before odors seep through.

For a limited time, we are offering a free Break Through Indicator when you order the MNHL Manhole Odor Insert or the SWV Super Wolverine Filters (a $22.95 value).