barbcnm@babymattresscovers.com Wrapping Demonstration can be viewed in our captioned Photo Gallery This is a Size E BabeSafe­® mattress cover Measurement Help: To measure the girth use a tape measure and wrap it around the mattress, measuring twice the width and twice the thickness. Feel free to e-mail us if you need further assistance. The girth is the most critical dimension. Measure with a tape measure completely around the width and thickness until the tape ends touch.