There is more in post #89 here about the pros and cons and the tradeoffs involved in different types of mattress covers which would apply to any mattress. The Dormeir is thinner relative to other types of wool/cotton protectors (it has 4.5 oz/yd of wool) and would have less effect than a protector that was less stretchy or used thicker layers of wool (see this post for some recent feedback from one of the members here) but a knit cotton protector will be more stretchy yet and would have even less effect than the Dormeir (although of course it wouldn’t be water resistant).