5SeabedBottom-ZBottom contour is indicated as astraight line and expansion view ofcertain area from its contour isshown. Zoom rate is set in MENU 1Zoom: ×2.5, ×5, ×10.BRILL【BRILL】key is used to adjust the LCD brightness.MENU【MENU】button facilitates selection of MENU 1, MENU 2, quit MENU.OK【OK】button confirms the setting value and quits from MENU.DISPFrequency displayed toggles among 50 kHz, 200 kHz, 50 / 200 kHz.MODEThree modes are optional toggled by pressing【MODE】key:Normal modeDisplay normal echo graphic.Bottom-ZBottom contour is indicated as a straight line and expansion view of certainarea from its contour is shown.Fixed-ZExpansion display a certain area.Arrows (UP▲/DOWN▼/LEFT / RIGHT )UP▲/DOWN▼: select the item of the MENU.LEFT / RIGHT : set value of item selected.