GX-8000 Sensor thermal conductivity TE-7515, GX-8000 Sample Draw Portable Multi Gas Monitor. The GX-8000 Marine Gas Monitor sets the new industry standard for rugged, reliable portable gas detection. It’s tough, water proof design utilized features based on years of gas detection design experience, to assure that the instrument will operate properly to protect workers and property in all kinds of harsh gas detection applications. GX 8000