Features: 4 levels grayscale LCD display with white LED backlight provides clear reading even when fishing at night or in overcast weather. Backlight brightness is adjustable. Display water temperature and depth, fish depth and location, weed detector, bottom contour and battery strength. Adjustable 10-level sensitivity settings and multi-level depth ranges. Depth reading ranges from 0.6m to 72m (2-240ft). Audible fish and depth alarm. Clear fish icon and fish depth indicator. Auto zoom bottom tracking and quick manual zoom. 200KHz/83KHz dual beam sonar frequency. Stop chart at any time. Anti-interference from the grass when used in lake. Built-in rechargeable lithium battery, charging voltage: 5V. Compact portable unit fits easily into your tackle box or pocket. Can be used in sea, lake, river, pond or other fishing environment.