Size Test&Control Technology (Shenzhen）CO., LED was established in Qianhai, Shenzhen in February 2021.

Size Test&Control Technology (Shenzhen）CO., LED is a new company under STT group, which mainly operates the air tester which named STT Fairy. Founded in 2008, STT has been committed to the leak test industry, providing professional detection equipment, instruments, solutions and services for the safety, environmental protection and energy-saving products. STT has rich experience in vacuum technology, air leak detection, helium leak detection, automatic control system, etc. STT has core intellectual property rights and has obtained more than 50 patents. The company's products are widely used in automobile parts manufacturing, air conditioning and refrigeration parts manufacturing, chemical packaging manufacturing, new energy battery manufacturing, 3C electronic products manufacturing, medical device manufacturing and packaging equipment manufacturing. Up to now, customers have spread all over 12 countries and regions such as China, the United States, Singapore, South Korea, Malaysia and Taiwan. The company was rated as "high-tech enterprise" and "specialized, distinctive, special and new enterprise" in China.

STT has two product lines. One is helium detection equipment, which is used in the field of high-precision leakage detection, providing support and services in vacuum technology, helium leakage test and system integration. The second is the air leak tester which named STT Fairy Series. According to different testing needs, in 2021, STT decided to separate the two kinds of productions for operation. Therefore, a new company was established in Qianhai, Shenzhen to operate the STT Fairy Series tester business independently.