Bumkins Reusable Cloth Diaper Contour Soaker Bumkins Contour Soakers are specifically designed to fit most brands of cloth diaper covers. Made of cotton, blended with 30 % bamboo rayon, they provide a soft, luxurious feel for optimum absorbency. Pocket opening allows option to add extra absorbency, if needed. Newborn size fits 5-12 pounds. *Diaper cover is required!