Run 619 4.5mm flat insoles offer a firm, zero-drop platform designed for versatility and daily reliability. Built from high-density EVA foam, these insoles deliver a supportive layer without altering your natural stride. The 4.5mm thickness is suitable for most footwear, featuring a traditional forefoot shape and no arch support. Use them as standalone insoles to replace worn factory inserts, layer them under custom orthotics, or fill extra space in roomy shoes and boots. Available in eight sizes and easily trimmable with scissors for a precision fit. These insoles work across a wide range of footwear including running shoes, hiking boots, work boots, and casual footwear. The firm, closed-cell EVA construction maintains its structure over extended use, providing a reliable low-profile layer for everyday movement. Not soft or cushy, the firmness is intentional, these insoles are built to hold up under daily wear. They can also be used to accommodate minor leg length differences. Tested by ultra-runners and designed for those who spend long hours on their feet.