A ~6-7" x 1" or 1 1/2" foam strip on the headband is ideal.  Small amounts can be bought here:

https://www.mcmaster.com/8694k93

Large quantities here:

https://foamforyou.com/volara-with-adhesive-backing.html

Different types of elastic can be used, from 1/4" - 1" flat type or a small round profile.  We are still testing options.  Small quantities can be bought on McMaster:

https://www.mcmaster.com/elastic-banding

Let us know if you find a good supplier for large quantities of elastic!  It's possible to use rubber, and I will likely release a design for using a large rubber band soon since they are cheaply and readily available (though less comfortable).

I can modify files for a specific thickness or dimensions of sheet if needed, as well as the hole geometry for the type of elastic used.  

Feel free to use this design under the Creative Commons CC BY-NC 4.0 license to help care givers in your area. Let's get our care providers the gear they need! 

This design was supported by and prototyped at Living Design Studios Inc www.livingdesignstudios.com a custom high end metal shop based in Erie, CO USA