Cycle caps are some of the more retro and identifying bicycle complements. We often tend to think that cycle caps and bands are part of the gear that is purely aesthetic. But like all garments, they have their function.
Their main function is to stop the sweat from the head running down to the face. They also help protect the head from the cold in winter or to reduce the effect of the sun in summer (even more so if we're 'old school': soaking it in water to keep the head cool for a good while.)
But if there is an element characteristic to cycle gear, that is the cycle cap. Fashion and designs play an important part in sports gear and cycling is no different. Which is why the major gear brands or cycle teams such as the Movistar Team have their cap in the product catalogues.
The bands have a similar function, useful in periods of heat or cold and beanies for winter cycling. The winter bands and beanies are characterised for being made with fabrics and technologies specific for maintaining heat, whilst offering breathability, ventilation and waterproofing. One of the main features is their design with greater cover of the areas more susceptible to the cold, such as the ears or the forehead (in the case of the bands). But if you ride around with your ears protected, don't get distracted! Especially if you're a city biker or if you get around on a road bike, be careful and check your manoeuvres twice, as with your ears covered, your auditory capacity is reduced.
Finally, the summer bands are made of more absorbent and ventilated fabrics in order to retain the sweat without it running down your face. Sometimes, the bands are replaced by head scarves under the helmet.