Wool insulator pads are often used to make your mattress more breathable and add some more bounce and fluff. This can be used inside the mattress outer or on top of the mattress and under a sheet. It can also be used in between a mattress and slats for breathability and to prevent mold. 
I use them on all my pet beds as well. 
Natural Untreated Wool absorbs vocs cleaning your air so you can breathe...
These are almost 1/4" thick and just pure felted Ecowool. 2.5 lbs per linear yard
 
Woolgatherer is a 100 Organic Certified Processor and Handler of Organic Fibers and Textiles Oregon Tilth CA OTCO CO 08 01082 since 2008. 
EcoWool comes from organically raised California sheep and then processed without any chemicals, in the facility where we do organic wool. 
This guarantees us the purity we expect for our chemically sensitive customers.