We've been using Ultra Pearls cat litter since we adopted Maggie and Aggie in November 2005. Great product, doesn't track, absorbs well and has no odor. Unfortunately, my husband found a piece of glass in one of the litter boxes tonight, way on the bottom. Very thin glass about 3/4" long by 1/2" wide. I've contacted the company and told them I'd be posting the information on different animal related website to warn other cat owners. Please be careful if you use this product. Thanks!