It is for weighing
the tongue, not the wheels.
Also, it is most accurate in the middle of the scale ( 1,000 lb. on a 2,000 lb. scale ). I replaced my gauge with a 1000 lb. which places my 320 lb tongue weight
at about the 1/3 mark on the gauge.
Trying to read a 250 lb. tongue weight
on a 2,000 lb. gauge is not easy, nor perfectly accurate.