Ridge Cap Shingles
The point where two fields of a roof meat at a peak is the ridge. The shingles you install over this point is ridge cap.
Like the starter shingles, ridge cap can be made from 3-tab shingles by cutting off the tabs and using the resulting piece of shingle. All roofing material manufactures also produce ridge cap shingles, and many are designed to be matched with a specific field shingle. However, low-end roofing shingles often rely on the less-expensive starter shingle made from 3-tab by cutting.
Though this video is for IKO brand products, it is a good representation of ridge cap install and options.