SAE 5-Bolt Pattern Focus Tube w/Dead Band EliminatorFocus tubes allow the TLM100/TLM150 ultrasonic tank level monitors to be used for level measurement on vessels with non-displacement hulls at up to 15Adeg of pitch or roll, compared to 6Adeg pitch or roll for the sensor alone. Additionally, the focus tube with deadband eliminator raises the TLM100/TLM150 2" above the top of the tank, allowing accurate level measurement with fluid levels all the way to the top of the tank, and eliminating the 2" deadband of the TLM100/TLM150.WARNING: This product can expose you to chemicals including NICKEL (METALLIC) which is known to the State of California to cause cancer. For more information go to P65Warnings.ca.gov.