Quick Response -
I recently got in touch with Della Zheng from Beijing Jin Rui Innovation Technology Development Co., Ltd. I was surprised to receive a response from her a few hours after sending the inquiry, which was very prompt. She also asked me technical details and she obviously knows their products pretty well.
It would be nice to visit their factory to check the quality of their products in person but I would definitely consider their company to my supplier list because of their fast and direct approach.