(Plastic) Plastic advantages: The entire product is washable, so you can always keep it clean at all times, and you dont have to worry about rusting so your cat wont hear sound even when it moves around in, so it is highly recommended. (3-tier type) This is a 3-tier type that is recommended for 2 people.Three scaffoldings allow you to perform better in the cage. (Wide 31.9 inches (81 cm)) Wide 31.9 inches (81 cm) wide, so your cat will not be able to perform insufficient exercise.