60' scale and it changes to the 0-30' scale, the entire screen will look as if you had been in the 0-30' range all along.

2.Using zoom and bottom-lock. Through Pixel Memory Capacity, the memory in the TCR ID-10 stores readings in much finer detail than is displayed in the "regular mode. So when you activate the zoom or bottom-lock functions, the entire screen changes to display the up-close detail that is stored in memory. Then when you turn off the zoom or bottomlock, the whole screen will change back to the full depth scale.

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Image 15
Humminbird TCR ID-10 manual