Quote from piezoe:
Hey, Spindr0 was nice enough to give you two very good answers. He told you what to Google to find out what a collar was, and then he explained that using the word vertical in conjunction with collar is superfluous. You can just call it a collar. The least you could do would be to thank him for his time. Now go and do some reading on collars.
Are all collars vertical or can they be diagonal? If so, how do you specify which collar you are speaking of?