Siemens
Honeywell
Vaisala
SenseAir (Asahi Kasei)
Amphenol Corporation
Cubic Sensor and Instrument Co.Ltd.
Sensirion AG
Trane
E + E ELEKTRONIK
Figaro
Gas Sensing Solutions
Digital Control System Inc
Zhengzhou Winsen Electronics Technology Co. Ltd. (Henan Hanwei Electronics)
ELT SENSOR Corp.