Instead of a one-size cover, Thirsties opted for 2 sizes. This helps to alleviate some of the sizing gaps that one-size diapers can create, and better fits babies on either side of the size spectrum. Depending on the diaper underneath, my 7 month old can actually use the size small or medium covers. I opted for the size 2 Duo Wrap since I figured I'd get more use out of it. She fits very well on the smallest setting. The Duo Wrap is trimmer than the sized covers. While it's not the best fit over a bulky fitted, it's great over trimmer fitteds and prefolds. I was able to use this at night with a prefold and hemp insert without any issues. Since she's on the smallest snap setting, I was able to use a bulky fitted under it by moving it up a setting. This is a trick you can try if you're not on the largest setting.
Overall, I think I love this covers as much as my sized Thirsties. The colors are great (meadow and storm are my favorites). Our Thirsties covers have always lasted us such a long time, and this is a way to maximize them even more. If you love Thirsties, you'll probably need to check out the Duo Wrap!