Single size fits 39" x 75" mattresses 550+ fill power with a 100% fine cotton shell Summer weight is lighter and cooler than 4 season weight Mature bird feather clusters are larger and have a higher fill power, producing more air pockets to increase both breathability and insulation Baffle box construction enables more evenly distributed fill and eliminates cold spots associated with down shifting 4-way baffle box construction and double stitching with white piping ensures long-lasting durability and comfort UltraFresh Hypoallergenic treatment deters bacteria trapping using anti-microbial preparations Downmark label ensures product meets requirements of the Down Association of Canada Made in Canada