Ultimate odor control - multi-layer refill bag with odor-locking barrier technology that prevents odors from escaping. Fits various dog waste - Dog waste, dog poop bags, dog diapers, training pads and dog litter. Long-lasting - One refill lasts up to 4 months for one pet. Easy to use - Refills are easy to insert, easy to dispose of. Flexible - Square refill contains continuous film, allowing you to cut and tie it to any length.