The 3243 Manu White Block is a nutrient-packed chewing delight for your pretty Polly! This natural mineral-rich clay is found on the banks of the Manu River, flowing all the way from Peru's Andes to the Amazon. This river always has birds flocking to it to eat the mineral-rich clay. Manu has the same nine minerals that are found in the wild clay, providing your pet with a wonderfully healthy way to get their needed minerals. The back of the Manu White Block has a threaded bolt, pan washer and wing nut making it easy to install the block inside your pet's cage. The large size gives your pet plenty of delicious and nutritious clay!