Cork Mat 6mm thick, round 75mm diameter. Bulk pack of 500. Cork is a completely natural raw material, with unique properties. More than half the worlds cork comes from Portugal. The tree has a lifetime of 170 – 200 years and the harvesting of the bark is absolutely harmless to the tree. The bark grows back within 9 – 10 years and can then be harvested. More than 85% of its volume is filled with air which makes it light, impermeable to liquids and gases, elastic and compressible, provides thermal and acoustic insulation, it is a fire retardant and highly abrasion-resistant. Cork sheets can be easily cut and are perfect for pin boards, model making and even acoustic insulation.