An easy, clean, convenient alternative for busy dog owners. The Second Nature Dog Litter System is an easy, clean, convenient alternative for busy dog owners. Three years of testing and development have gone into the creation of Second Nature to ensure its effectiveness. Made from natural, non-toxic and super absorbent recycled paper, it's dust-free and non-tracking. Please Note: Litter pan and litter must be purchased separately. A training guide is included with each bag of litter. Size: 25 Lb.