After years of solid and rapid development, SONC has grown into one of the most professional and influential enterprises in China. footwear maker machine SONC is a comprehensive manufacturer and supplier of high-quality products and one-stop service. We will, as always, actively provide prompt services such. For more details about our footwear maker machine and other products, just let us know.The product has effective sealing. The hydraulic seal and other spring seal work together effectively to enhance the airtightness.