What goes on inside your retractable leash is a complex mechanism with springs, coils, buttons, levers etc. etc. etc. Each part is crucial for optimal performance of your Wigzi leash. If any one part breaks then the whole thing usually just taps out. With that being said we want you to have the leash for years and trust Wigzi and come back and buy more and the only way to do that is to invest in quality. We've grown to be an international pet products brand and want to keep it that way. The main engine of our leash is our retractable spring. It is the most vulnerable part because it gets used the most. In and out...in and out multiple times a day, rain or shine. Rain is actually the enemy. Moisture collects inside the leash and most retractable springs which are made of alloy metal just rust out and break. Our retractable spring is made with stainless steel and a touch of chromium so it prevents rusting with moisture. Our in and out cycles exceed 149,000 times so you know you're good for a long time.