Fleece makes for a very soft, comfortable wrap and although fleece is not inherently waterproof it is ultra absorbent and great for night time use.
How do fleece wraps work?
Although fleece wraps have no waterproof layer the fleece effectively stops wet getting through. In addition to acting as a water resistant barrier, because fleece is breathable and therefore lets lots of air circulate around the nappy, the nappy inside should acutally be less wet than the same nappy inside a PUL wrap.
The good air circulation is great for the skin and you won't find a hint of sweatiness or overheating with either fleece or wool wraps when used overnight - even in excess of 12 hours!
Because the wraps work by slow evaporation and air circulation they do need to be a roomy fit to work at their best. Tight clothes, pyjamas or sleepsuits poppered tightly under the crotch can all cause 'compression wicking', pulling wet through the fleece as it is squashed against the wet nappy inside.
Having a wrap that is too big is always preferable to a tight one and as long as the legs and waist are a reasonably snug fit you shouldn't get leaks even if the wrap is quite loose through the body.
This popper-fastening fleece wrap is perfect for night time. Fleece is soft and breathable water-resistant so even though there's no PUL layer in these wraps they won't leak. The fleece allows more air to circulate than a traditional PUL wrap so the skin stays drier inside the nappy.
We don't generally recommend fleece wraps for daytime use as sitting for any length of time will cause compression wicking (wet being squeezed through to the outside world!)