GPM gearbox question

Hello I am wondering what is the difference between the following products by GPM?

KM012A ALLOY GEAR BOX WITH SCREWS (LARGE TEETH DESIGN)
KM012 ALLOY GEAR BOX

The "large teeth", does it mean the pinion? Like it can use larger pinions? What is the range of each gearbox pinions? I am going to be running a brushless motor in the kyosho hor.

Thanks!
Jackson

I haven't try the 'large teeth design' one, I think it can fit in the 14 teeth pinion without any modification. (The ordinally one have to cut a little bit)

Thanks!