There are no accurate bodyfat% scales that you can buy somewhere in a store
the best thing that you can measure with ANY of those devices (that includes calipers) is progress, e.g. always measure under the same circumstances and you'll see whether you bodyfat% decreases or increases.
Any absolute number you'll see on a display has an error margin around 5%, which would be nearly half of the absolute value you want to know in the first place which means you can pretty much ignore it or roll a dice instead
submerging tanks are not more accurate either
IF you really want to know your bodyfat%, you'll have to get your body analyzed with a special machine that uses x-rays at a laboratory, some bigger better equipped hospitals have those, costs well over 1000$