Maretron DST100 & DST110 Bronze Housing Kit - Transducer Not IncludedThe DST100's bronze housing includies a blank plug to replace its sensor unit when the vessel will be docked for extended periods or trailered. This prevents damage to the sensor and reduces fouling growth. 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.