Mattress Protector vs Mattress Encasement

Fitted protectors are easier to remove; zippered encasements surround more of the mattress.

Fitted protector

A fitted design installs much like a fitted sheet. Coverage can range from a waterproof top to waterproof top and sides.

Encasement

A zippered encasement wraps around the mattress more completely. That can be useful when full enclosure matters, but laundering and installation take more effort.