These are basically Fatshark goggles straps but with an added neoprene pad. This makes for a more comfortable fit and allows your goggles to stay on nicely throughout your flights.
The elastic membrane in these straps is harvested in the far reaches of the Indonesian rainforests, where natural plantations of rare species of rubber trees thrive. In order to grow to a ripe old age, this rare rubber tree can only be harvested once per decade. We timed it right, and there it is. The super rare Armattan strap for Fatsharks. (May work with other brands, too.)