Clean Rest Pro Bed Bug & Allergen Blocking Box Spring Encasement Featuring Zip-N-Click (Twin) CleanRest PRO Box Spring Cover is to be used in conjunction with the the PRO Mattress Encasement. Certified 100% Bed Bug Entry, Escape and Bite Proof. Breathable - Water Resistant - Washable - Blocks Allergens Surrounds and protects the box spring on all 6 sides against allergens, dust mites, bed bugs, bacteria, fluids, perspiration and urine (15-year warranty and machine washable) Premium MicronOne surface material with breathable hypoallergenic membrane backing keeps the mattress cool and quiet while blocking dust mites and other allergens (great for those with asthma and allergies) Secure zipper closing with Zip-N-Click prevents accidental openings by sealing the end zipper traveler with a secure cap.