All four that I bought (2 sets of 2) seems to be working just fine. This is the first set that we didn't buy that didn't zip around the entire mattress.
Biloban Box Spring Cover (4/5/7/9/13/17Inches) Twin, High Profile Waterproof Mattress Protector, 6 Sides Wrapping Zippered Mattress Encasement Cover
34 Review
Twin Mattress Protector Waterproof Soft & Breathable Terry, Noiseless Mattress Cover Fits Up -14'' Depth, Skin-Friendly Machine Wash Mattress Protector
29 Review
RV 6 Sided Zippered Mattress Protector With Secure Locking Zipper For 70X80 RV King. Creates A Natural Seal Around Your Mattress From Dust, Pet Dander, Pollen, Liquids & More. Oeko-Tex Certifiedโฆ
14 Review
Waterproof Twin XL Mattress Encasement With Zippered 6-Sided Cover, PlushDeluxe Premium Quality, And Cotton Terry Surface (Fits 12-15 Inches H)
14 Review
Stylish Bracelet Replacement Band With Diamonds For Fitbit Versa 2 Smart Watch - Compatible With Fitbit Versa, Versa Lite, And Versa 2 Bands For Women - Silver
28 Review
Secure Your Swing With Safe And Easy Tree Swing Hanging Kit - 2000 Lb Breaking Strength And Quick 10Ft Long Strap Installation
34 Review
Gulrear Portable AC Window Seal Kit - White 400CM/158Inch Hot Air Stop Exchange Guards With Zipper And Adhesive Fastener
38 Review
Black 2-Pack Of Vivere EFHTS Accessories For Hammocks
27 Review