We must realize that mattress encasement are just like mattress covers. They may just have a different name. But they serve the same function and that is to protect the underlying mattress and it must be the right size of mattress encasement to fit the mattress. You better make sure you buy one that has enough depth to cover the mattress as well. Preferably the mattress encasement will tightly fit over the mattress. It would be nice if it had a removable cover that is machine washable and easy to remove. It should be able to prevent dust mites, bed bugs, and mold. It should allow air to free flow through it so the customer sleeping on the bed will not perspire which will make them overheat and sleep very uncomfortable.