Feather Friendly has solutions for all types of glass. Whether it be reflective or mirrored glass, fly-through surfaces, or combination glass, we have a solution for you! White markers are recommended for reflective or mirrored surfaces while black markers are recommended for fly-through surfaces. Having trouble deciding which is best for your glass? Visit the link in our bio! #birdsafe #windowmarkers #glasscollisions #reflectiveglass #flythroughglass