Our felt and cork insoles have very similar features.
They both have a thickness of 3 mm and therefore give a softer ground feel. If you have narrow or low-volume feet, they help you get a better fit in your Feelgrounds, and on colder days, they provide extra insulation.
Both removable insoles are also great for protecting the sewn-in insoles of your Feelgrounds as you can just exchange the removable insoles in case they wear out, get dirty, or smelly. The cork insole is especially great if you plan on wearing your Feelgrounds barefoot because cork is a natural material that provides a great foot climate.
All in all, it depends on your personal preference of material which insoles you choose. Some of our customers wear felt insoles in winter and cork insoles in summer, although both can be worn all year round.