AM177-2 Motor Mount for A800MMX/A made from high grade 7075 T6 alloy. 
The new version features an increased slot for the ESC wire to allow an easier electronics installation. 
Additionally, the AM177-2 has the Belt Anti Skip unit integrated
To make use of this, you need additionally 1x B73SS ball bearing and 1x SB3X5 screw.
(INFO - A800-BAS set is not suitable to use with AM177-2)
It's a direct replacement for AM177.