How to reverse object connected to null after reaches a certain position in x or y

[Kalleheikki Kannisto]

Do you mean reverse the direction in which the hand is moving or flip the hand?

If you want to flip the hand when going beyond certain x or y value, apply this to the scale value:

scale_x=transform.scale[0];
scale_y=transform.scale[1];

if (transform.position[0]>1100 || transform.position[1]>750){
[-scale_x, scale_y]
}else{
[scale_x,scale_y]
}

replacing 1100 and 750 with your own limit values for x and y