AllerZip Smooth Waterproof Bed Bug Proof Zippered Bedding Encasement, King, (Fits 7-12 in. Deep)

Can this be used for either a mattress or a box spring? I want to order one for a queen mattress and another for the box spring.

does this need to be washed before using it? (so that its waterproof)

My matress is 12 inch I notice it say 12-14 inch would it be loose fitting? Read every single review but no mention about it.

Is this product lab tested and scientifically tested and certified?