Each material that you'll typically find in an insole has its own advantages and disadvantages. EVA foam insoles are the most common type of insoles. EVA foam is great for absorbing pressure while still maintaining its shape, and insoles made of this material are lightweight and easy to trim if necessary. Gel insoles are excellent for absorbing impact shock, but they tend to not hold their shape well under pressure and tend to be relatively heavy compared to insoles made of other materials. Cork insoles are breathable and rigid to ensure that their shape is maintained, but they tend to lacks some of the cushioning properties of insoles made from other materials. Memory foam insoles are great for having a nice layer of plush cushioning that will not only improve pressure relief but will also conform to your feet over time. The major downside to memory foam is that it compresses much easier than EVA foam and may not hold its shape as long. Lastly, carbon fiber insoles and insoles made from other similar composites are extremely rigid and ensure maximum support, but they don't flex freely.