Sentence:The locking mechanism for a [e1]gear[/e1] consists of a [e2]collar[/e2] (or dog collar) on the shaft which is able to slide sideways so that teeth (or dogs) on its inner surface bridge two circular rings with teeth on their outer circumference: one attached to the gear, one to the shaft.
 e1: gear. 
 e2 : collar.
Answer: Component-Whole(e2,e1)