Is full crystal from the fuller brush company. the fastest, easiest way to clean all of your windows in minutes, not days. just add the cleaning crystals, attach it to any garden hose and away you go. the secret is in the fuller cleaning crystals that dissolve dust dirt, pollen and grime in no time. and here's the best part you don't have to remove your screens because full crystal cleans them to watch what i'm going to do. this screen may look clean but look out for crystal blast away the dust ball and dirt and grime while it cleans your window at the same time and that'll save you a ton of t...