A visit — yours or an inspector's — is the surest check on a new supplier. Send a date and what you want to see; the request reaches them as an enquiry you can track.
Address
Room 301, 3rd Floor, Factory Building 4, Accelerator 3 of Weifang High-tech Zone Optoelectronic Industrial Park, No. 66, Yinfeng Road, Yulong community, Xinchen