Zoontron is the largest manufacturer of constant force spring in China, suitated in a beauitful city Zhuhai, Guangdong province.The company invested huge money and intelligence in past years,developed the most advantage automatic production line and applied full testing equipment.The company is now the number 1 spring supplier in China especially its constant force springs are massively installed in products like computer lifting base, pull-up window, pull-up curtain, car safty belt etc. We will continously be specializing on producing constant force spring, will offer best products to all valueble customers worldwide. Please kindly be noted that we are not only provide wide range products,but also accept customerlized constant force spring.