Recommended models: 750C-6498, 740-D8018
 
China is a big lock country, with a total lock export trade of 3.839 billion US dollars in 2017, accounting for 31% of the total global lock export trade. And China's mechanical lock market and technology is quite mature, as early as 2011, there are about 1,000 door lock companies with annual sales of more than 5 million yuan. Guangdong, Zhejiang, Shandong and other places have mature lock-making industry clusters. Among them, Xiaolan Town, Zhongshan, Guangdong Province is one of the representatives, known as the "Southern Locked City".
 
Backed by Zhongshan City, a mature hardware production base, Xiaolan locks accounted for 40% of the domestic lock market in 2011, accounting for 37% of the country's total lock exports. In terms of products, Xiaolan locks are mainly handle locks and spherical door locks, which are also the main production categories of lock enterprises in the south, which are different from padlocks and various vehicle locks in the north. In addition, Guangdong lock companies produce more high-end door lock products, while enterprises in Zhejiang and other places occupy the low-end lock market.
 
Yuema is a lock brand from Zhongshan Xiaolan, and has excellent technology in mechanical lock cylinders. Its founder, Li Deshan, has developed the first motorcycle lock in the traffic lock industry, and later he continued to transform the lock cylinder structure and designed two sets of side posts and two sets of blades of the lock cylinder, which is more effective in preventing the technology from opening. In addition, with the patent of the idling lock cylinder, Yuema locks began to make a name for themselves in China, accounting for almost 80% of the Chinese lock market share in 2014.
 
In the field of exterior door locks, Yuema has launched two products, 750C-6498 at 280 yuan and 740-D8018 at 129 yuan. In the model, the numeric prefixes such as 750 and 740 are not unique to these two products, and can be seen in most Yuema locks, which represents the lock cylinder series to which the model belongs. Yuema has a total of 730, 740, 750 and 760 lock cylinder series, the larger the number, the higher the product positioning, and the higher the safety of the lock cylinder technology applied. All of these series use Yuema's core idling lock cylinder technology, which can prevent technical unlocking such as code detection and unlocking, and the difference between different series is mainly reflected in the blade structure and some details of the design, the higher the positioning of the series lock cylinder structure, the more complex the structure.
 
Elsewhere, the 750C-6498 and 740-D8018 are equipped with C-class cylinders for the highest level of security. The appearance of the two is almost the same, it is a common multi-tongue door lock, and the deadbolt structure is 1 oblique tongue and 2 dumb tongues, and it can be locked in three sections. Their housings are made of solid alloy steel, which provides a high level of overall safety.