A mattress and box spring are too expensive not to protect!  If you want a cover that will protect your mattress and box spring from spills, stains, allergens, bed bugs, dust mites and dust particles we recommend our Night Watch cover.  It fits on the mattress like a bag with a zipper closure and is available in two depths; 8 inch and 15 inch.  Buy two: use one on the mattress and one on the box spring.
Night Watch Hypo-Allergenic Mattress Protector available in the following sizes: 
8” Depth:
Twin (39X75X8)
Twin Extra Long (39X80X8)
Full (54X75X8)
Queen (60X80X8)
King (78X80X8)
15” Depth:
Twin (39X75X15)
Twin Extra Long (39X80X15)
Full (54X75X15)
Queen (60X80X15)
King (78X80X15)
Also available in Standard, Queen and King sizes to protect your fine pillows.