Brita Water Filter Bottle Replacement Filters, (4 Count) 4 count of replacement filters that fit all Brita Hard Sided Bottles and Brita Sport Bottles 1 water filter can replace 300 standard 16.9 ounce water bottles Filter sits inside water bottle, reducing particulates and chlorine taste and odor, often found in tap water For best performance change filter every 40 gallons or 2 months BPA-free replacement water filters require no pre-soaking