Tesoro's new Sand Shark combines time-proven PI circuits with the latest digital technology creating the first microprocessor controlled PI detector for the new Millennium. Pulse Induction (PI) detectors have always been the natural choice for working wet salt beaches. Their circuitry and single loop coils will not see changes in salt-water conductivity that drive a VLF-style detector crazy. Add Tesoro Electronics' exclusive interchangeable Printed Spiral coils (available in four sizes) and you create a fantastic PI detector. But we didn't stop there. The Sand Shark has two distinct operating modes: VCO and Normal. When working in the VCO mode, as targets get closer to the coil, the threshold generates a louder, higher pitched tone great for pinpointing. The Normal mode works with a single tone and is used for beachcombing and other prolonged searches. We've added a microprocessor to help you customize the detector to your specific needs. Our Pulse Width control allows you to tune your detector to the best balance of depth, sensitivity, and battery life. You can also change the Normal mode audio frequency. Simply use the "F" Adjust knob to set the tone and you're ready to go. The Sand Shark also has a new drop-in battery compartment for quick and easy changes. The Tesoro Sand Shark will change the way that you think about pulse detectors.