| Sun Lee Air Duct Limited | Private company limited by shares | Live |
| ON KONG ALUMINIUM DUCT CO. LIMITED | Private company limited by shares | Live |
| DURA DUCT (CHINA) LIMITED | Private company limited by shares | Dissolved |
| XIAMEN UNT DUCT MATERIAL CO., LIMITED | Private company limited by shares | Live |
| WIN POWER DUCT ENGINEERING LIMITED | Private company limited by shares | Live |
| INTERLOCK FLEXIBLE DUCT (HONG KONG) LIMITED | Private company limited by shares | Dissolved |
| SUN LEE AIR DUCT (HK) LIMITED | | Live |
| SKYLANE PACIFIC AIR DUCT (H.K.) LIMITED | Private company limited by shares | Dissolved |
| Hong Kong ABB Bus Duct Co., Limited | Private company limited by shares | Live |
| DURA DUCT HONG KONG LIMITED | Private company limited by shares | Dissolved |
| HONG KONG SPIRAL DUCT LIMITED | Private company limited by shares | Dissolved |
| SHANGHAI HUATE DUCT INDUSTRY GROUP LIMITED | Private company limited by shares | Dissolved |
| DUCT IMPORT & EXPORT CO., LIMITED | Private company limited by shares | Dissolved |
| HK PIERSA DUCT INDUSTRY GROUP LIMITED | Private company limited by shares | Live |
| SHANGHAI PIERSA DUCT INDUSTRY GROUP LIMITED | Private company limited by shares | Live |
| SHANGHAI PIERSA DUCT INDUSTRY GROUP LIMITED | | Live |
| HK TIANDE DUCT INDUSTRY LIMITED | Private company limited by shares | Dissolved |
| DURA DUCT INTERNATIONAL LIMITED | Private company limited by shares | Dissolved |
| PLATO AIR DUCT CLEANING LIMITED | Private company limited by shares | Live |
| FO SHAN NAN HAI FORTIS DUCT LIMITED | Private company limited by shares | Live |
| PACIFIC WING SHING AIR DUCT COMPANY LIMITED | Private company limited by shares | Live |
| DELTA DUCT SYSTEMS LIMITED | Private company limited by shares | Live |
| DUCT ZONE LIMITED | Private company limited by shares | Live |
| XUZHOU EVERBRIGHT SINSING DUCTILE IRON PIPES CO., LIMITED | Private company limited by shares | Live |
| BENXI BEITAI DUCTILE CAST IRON PIPES TRADING CO., LIMITED | | Live |
| GUANGDONG AOXINYU DUCTILE IRON PIPES CO., LIMITED | | Live |
| DUCTILE INVESTMENT COMPANY LIMITED | Private company limited by shares | Live |
| DUCTMASTER AIR CLEANING LIMITED | Private company limited by shares | Dissolved |
| PERFECTA DUCTS MANUFACTURING CO. LIMITED | Private company limited by shares | Dissolved |
| TECHNIC DUCTS LIMITED | Private company limited by shares | Dissolved |
| DUCTUS COMPANY LIMITED | Private company limited by shares | Dissolved |