This is a way of marking territory if they are rubbing the sides of their faces on the object. Cats have scent glands around their lips and on their chins. The facial pheromones that they mark with are signals of a happy or calm cat to other cats.
The part that simultaneously enables the axle to flex while transmitting the driving force is called a drive axle joint, and is also known as a constant velocity (or CV) joint. The CV Boot is a ribbed, rubber flexible boot that keeps water and dirt out of the joint and the special grease inside the joint.
VIN (Vehicle Identification Number) is a unique universal serial number issued to every vehicle by the manufacturer. Within the 17-digit number are codes that indicate the vehicle's make and model, the factory where the vehicle was manufactured, a serial number and information about optional equipment.