Hi MLSly,
The gaps on the easy fit are a little over 4" apart (see the foundation thread here) but they should be fine for a memory foam mattress.
post #89 hereThere are a couple of alternatives in the but they are also fairly costly compared to the membrane type. The Natura has a membrane so it may not be as breathable as a protector that only uses wool and cotton. Unfortunately wool is a more costly material and it’s just not as inexpensive to produce a good wool protector and there aren’t a lot of options for this type of protector.
Phoenix