The distinctive racing vest worn by cycling World Champions when competing in the discipline in which they won the championship. The canonical form is a plain white jersey with five horizontal bands of about 3cm width half way down in blue, red, black, yellow and green (top to bottom), the same colours as the Olympic rings (and thus supposedly including at least one colour from the flag of every country in the world); the cuffs and collar are also trimmed with the same bands.
There have been some variations on the design. For some years in the 1980s and 1990s the champions in minor classes (notably the junior and veteran events) received a jersey in which the stripes were in a V pattern; today the vests for events other than the road race bear a stylised blue motif for the discipline overlaying the stripes on the front.
The vest is not worn by the defending champion in the following championship race itself (they revert to their national team colours), but it has become normal for former champions and champions riding in other disciplines (time trial, track, cyclo-cross, mountain biking and artistic cycling) to have small rainbow stripes on their normal team jersey cuffs. Professional riders are awarded a plain vest in the official ceremony, but can wear one overprinted with the normal advertising for their trade team from the following day; they may also wear coordinated shorts rather than the team issue ones, a rule change probably prompted by the serious eyesore created by juxtaposing it with the incredibly messy Mapei team colours.
The rainbow jersey takes priority over a national champion's jersey in the relevant discipline, but is subordinate to a race leader's or classification leader's jersey in a stage race (which are usually tied in with commitments to advertisers) or to the leader's jerseys for World Cup competitions or the UCI ProTour.