CG Track

They are to help correct contact bias. If you tend to hit the ball off the toe side then you move the weight to the T1 or T2. If you tend to hit the ball off the heel you can move it to H1 or H2.

This is to very very very slightly shift the center of gravity towards one or the other to help keep ball speeds up and will move the sweet spot very slightly towards the toe or the heel respectively.