The Saturation Indicator is an easy method to detect contaminant breakthrough in a carbon bed. The indicator is constructed of a clear tube filled with a special media. This media is a bright purple color when new and changes to brown as it detects contaminants (H2S). When the media has completely changed to brown, it can be assumed that the carbon bed will need to be replaced soon. Simply remove the 3/4" NPT plug at the top of the Inline Wolverine and install the Saturation Indicator. Our saturation indicator now comes with a sun cover to prevent pre‐mature discoloration of the media due to sun exposure.