Recommended references are as follows:

1. Yajie Hardware (Guangdong Yajie Hardware Co., Ltd.)

2. Tiannu Hardware (Guangzhou Tiannu Hardware)

3. Huitailong Hardware (famous brand, Huitailong Decoration Materials Co., Ltd.)

4. Dinggu Hardware (Guangdong Zhongshan Dinggu Metal Products Co., Ltd.)

5. Siligao Hardware (Siligao (Nanhai) Technology Building Materials Co., Ltd.)

6. Mingmen Lock Industry (Guangdong Zhongshan Mingmen Lock Industry Co., Ltd.)

7. Paramount (Zhongshan Paramount Metal Products Co., Ltd.)

8. Damengdi Hardware (famous brand, Guangdong Rongsheng Metal Products Co., Ltd.)

9. Ikov (German brand)

10. Modern Hardware (Guangzhou Modern Hardware Products Co., Ltd.)