There are different types of mattress protectors. Encasements are shields that protect the mattress directly, typically from bed bugs, and are often used in hotels. Protectors are used to protect the mattress from bed-wetting or allergic situations. In contrast, mattress pads and mattress toppers are primarily used to provide comfort features for the user. Pads are thinner, while the thicker toppers tend to be more comfortable and expensive.