Expert eyes needed

Brass blocking rings or synchronize brass rings. The little teeth at the outer ends and the corresponding ones opposite them on the gears is what I'm talking about. The brass blocking ring is what slows the gear from spinning to complete the shift to the next gear. On the way down I mean downshifting, same thing they have to slow the gear down to complete the down shift. The more rounded these points are the harder the trans is to shift.