It is a patented foam, developed and patent belongs to RogersCorp, here is the official website for you if you want to know more details:
Poron materials are more popular in electric industry, as it is soft and shock absorbent, can protect the electric devices safely without increasing too much space one package, and also it is very light.
Some kind of materials are made in USA factory and some are made in Suzhou, China. Poron is used in shoe industry because its permanent elastic and outstanding shock absorbent properties. Beyond that, Poron is also very breathable materials. Should be noted that Poron is very expensive.