Western spurs used in western riding may also have small curved-up hooks on the shank in front of the spur rowel, called "chap guards," that were originally used to prevent the rider's chaps from interfering with the rowels of the spur. The shank angle from the yoke can vary from "full". to "one half", to "one quarter" to "straight". Some cowboys also added small metal Pajados, also known as Jingo Bobs or Jingle Bobs, near the rowel, to create a jingling sound whenever the foot moved and to have the horse move away from the sound. Rowels can vary in size and number of point and use is by discipline: Cutting, Roping, Barrell RacingReining, Working Cowhorse and Western Pleasure.