Whisper Bio Bag, Large Single. Disposable Filter Cartridge Clear water made simple. Single Assembled Large Cartridge (formerly known as Regular). Keeps water crystal clean, removes odors and discolouration, easy to use. They're tough on debris, Ultra-activated ® carbon absorbs odors and discolouration better than competing brands. Dense, dual sided mesh catches debris and fish waste. More debris trapping mesh than other products. Instructions for use on packaging.