Filtrete Under-Sink Standard Replacement Water Filter (3US-AF01)
From the Manufacturer Replacement filter for the 3M Filtrete 3US-AS01 Under-Sink Advanced Water Filtration System.  Product Description Filtrete Drinking Water System Refill. Now you can have cleaner, great tasting water at your convenience, fresh from your tap. Filtrete under-sink water filtration products are easy to install, with no mess, long lasting replacement filters that can be changed with just a twist.