The Horiba LAQUA 9551-20D (3014047090) Dissolved Oxygen Electrodes, For Field Immersible Type, 2m Cable. For field use, immersible, 2m cable. Operates with replaceable DO tip 5401 and built-in temperature sensor. For field use, immersible, 2m cable Operates with replaceable DO tip 5401 and built-in temperature sensor Waterproof.