MUL Gradiometer Magnetic Underwater Locator Kit w Sensor & Electronic Box bundle product KESOTR18300 Keson heavy duty fiberglass tapes are 316 001 705 Keson heavy duty fiberglass tapes are packed with the strongest possible fibers in the thinnest possible tapes to keep the weight down while keeping the blades strong This magnetic level set by Stabila features rare earth magnets that are flush mounted on the level’s measuring surfaces to provide additional reinforcement to its frame The bar graph fills to the left (negative) or right side (positive) depending on the signal polarity How it works:The Magnetic Underwater Locator (MUL) is a magnetic gradiometer that locates objects by detecting differences in magnetic field strengths using the two sensors inside the sensor tube housing