Question about Kibernetik KS50L

For me, the scale is from 0 to 5, and I have also set it to 3 (although certain things near the rear wall already freeze at 3).

There is a knob on rear marked 1 to 6 for temp control. I find 3 or 4 is good normal fridge temperature. 5 and 6 have been known to freeze drink bottles in rear overnight.