As promised they fit deep pocket mattresses.  To keep my sheets from sliding I also used my mattress pad on top of protector.  I miss being able to tuck my flat sheets between the mattress and box spring...I can live with that, but Not dust mites!!  TIP...B4 using your protectors, strip your bed, vacuum and steam your mattress. If you dont have a steamer use some antimicrobial febreeze. Zap those pest b4 adding the protector to your mattress.