SSI offers three families of ultrasonic liquid level sensors: Fluid-Trac, Acu-Trac SMART 485, and Acu-Trac. Fluid-Trac sensors come in 2-wire/resistive emulation and 3-wire/voltage output models, each with a distance accuracy of +/-0.125", range up to 32" and resolution to 0.07". The Acu-Trac SMART 485 gasoline and diesel level sensors, meanwhile, are designed as direct replacements for level senders on gasoline tanks with depths up to <1.9 m for gas and <2.5 m for diesel; accuracy is within 2% of tank volume. Finally, the basic Acu-Trac is available as regular, NEMA4, or Kynar package NEMA6, for real-time processing of fuel data and messaging over the RS-485 bus. They can be used for tanks with depths of <1.5 m, <1.5 m, and <3 m, respectively, with an accuracy to 2% of tank volume.