These are designed for the lovely wood Montessori bed. We make the bolsters in any size you need. These are for our 6"cylindrical style. Organic cotton damask filled with our pure nasty chemical free EcoWool.
 
And after you use these for this bed, you can later use for yoga, for neck support, in your chair, in your car. They will last over 20 years. 
Remember wool breathes twice as well as cotton, making these pillows a very safe option. 
Standardly you may need a front pillow to cover the partial rail that is 39", a 26" back rail pillow, a 75" back rail pillow, and a 32" top of the bed bolster.
You can get custom sizes should you need any.
 
We do make covers for these pillows in our various organic cotton fabrics. 
 
If you need to clean these, Hand rinse outer and let air dry, natural wool still has the natural lanolin that sheep produce in them so it resists liquids so it will be self protective.