How does your factory do regarding quality control?

How does your factory do regarding quality control?

A: "Four Steps" QC:

(1) Workers self inspecting,
(2)workshop inspector inspecting, 
(3)packing inspecting 
(4) finished goods random inspection in warehouse before delivering.
For new orders, mass production samples will be sent for your confirmation on quality for double insurance. Mass production pictures/video available for your reference.