Regitar USA Rotor f/Mercruiser Volvo Penta Inboard Engines: GM 4 Cylinder Engines w/Delco EST Ignition [RMN005] Brand_Blue Sea Systems It makes the depth scale

It makes the depth scale easier to read too

The intuitive manual control option simplifies operation and increases awareness of the state of the manual override and whether the device is being left in a locked-off or locked-on state (not available on competitive solutions)

making distance measuring much easier

Do not use it with a self-inflating PFD

Regitar USA Rotor f/Mercruiser Volvo Penta Inboard Engines: GM 4 Cylinder Engines w/Delco EST Ignition [RMN005] Brand_Blue Sea Systems It makes the depth scaleRotor for Mercruiser & Volvo Penta Inboard Engines: GM 4 Cylinder Engines with Delco EST Ignition Engine Brand: Mercury Mercruiser Volvo Penta Fitment: GM 4 Cylinder Engines with Delco EST Ignition Brochure (pdf)