The new Kuhl Plastic Nest Pads are designed with a slotted base as pictured, not only to allow air circulation but also to allow droppings to go through the nest pad. This greatly reduces the bacteria growth due to wet nest material. You will save a lot of time and labor with Kuhl Plastic Nest Bottoms. There will be no more filling nests with shavings and other nest materials when used with roll-out nest bottoms. The droppings fall through the nest. Washing and disinfecting pads is made easy because they are all plastic and water can go through the pad giving you a far more sanitary operation.