... sizeLarger valve with high flexibility film provide a lower breathing resistancePICS:About us:Founded in 2009, SUZHOU SANICAL PROTECTIVE PRODUCT MANUFACTURING CO.,LTD is ... , surgical masks, active carbon masks, valve masks, and facemasks. Company Name:SUZHOU SANICAL PROTECTIVE PRODUCT MANUFACTURING CO.,LTD Street Address:Xiangcheng District, Yangcheng Lake ...