The Superfeet Carbon Trim To Fit Insole is a lightweight high-performance insole for the dedicated athlete. With technology that has been developed over many years to create a low profile, lightweight & lower volume insole that is made from a carbon & polymer mix. For breathability, Superfeet have added perforations under the mid-foot & forefoot whilst still maintaining comfort & support. This insole will aid any athlete wanting comfort without compromising high performance. Features Carbon fibre-reinforced Innovative performance product Strong & lightweight Bevel foamed edge Low profile shape to stabilize Foam perforations reduces weight & increases breathability Antimicrobial coating to reduce odour Structured heel cup for support & position Specifications As with all new products, a break in period may be required. We advise you wear the products for 1-2 hours on your first day & build this by 1-2 hours until you are completely comfortable with the products. For some people this may take a week or two. It is not uncommon to feel the Superfeet products towards the back of the arch, in front of the heel. This is just the unique Superfeet shape doing its job. Please be aware of the 60 day money back guarantee if you are not completely happy with the products.