Racing Power Wheels Part 5: The Rear Axle and Parts

So lately I've been working on the axle and drive system and I have received the motor controller that was ordered from TNC Scooters and now the motor works now. I'm in the processing of trying to return the two motor controllers I got from Monster Scooter Parts so they can test them and see if they are faulty or not.

So I have received the axle, sprocket for the axle, brake disk kit, some collars, keys, a sprocket hub, and the wheels and tires. Below is an image of the axle with its components without the wheels. 

In the picture above, from left to right, you can see a collar, the brake disk, the sprocket hub with the sprocket bolted onto it, and then finally another collar. I'll go into a little more detail on each part that I have received so far for the axle.