This cover stands for its upgraded quality, windproof and anti-UV performance : 1. Great durability, anti-UV performance increased by 25%, thanks to 6 layers top fabric and 3 layers side fabric, anti-UV composition upgraded from 3% to 4%; 2. Ventile and windproof: air vent on both sides of the cover, 3 straps & buckles sewn at the bottom of the cover, 2PCS 42’ ALL-3. AROUND straps can tie around RV cover; 4. Three zipper constitute 2 zipper door at right side panel, 4 gutter spout covers with sponge inside