Andis04880 Blade Zero Gapper Tool For Outliner, T-Outliner and Styliner Blades

What does it do?

Will this work on the andis gtx?

Does this work on the styliner II blade? I dont recall an adjustable screw on those blades....how could that be zero-gapped?

this is hard to see, is this a trimmer or just blades? This cuts very close correct?