We recommend one cover for every 3 - 4 diapers in rotation (excluding diapers with waterproof exteriors). (thirstiesbaby.com)
Thirsties Diaper Covers are generously cut and offer a superior waterproof exterior on any type of cloth diaper you choose - prefolds, contours, or fitteds. (nickisdiapers.com)
The generous cut of the covers presents a superior waterproof exterior on any type of flat, prefolded, or fitted cloth diaper (overthemoondiapers.com)