Trouser protection
A trouser protector (also called a trouser clip ) protects the cyclist from getting his trouser legs dirty. It is attached to the end of the right pant leg.
A trouser protector consists either of a textile strip, which is fixed with a Velcro fastener , or of a round metal clip. In the past, metal clips were common, which, attached to the right of the trouser leg, pulled it tight.
By using such a trouser protector, the trouser fabric is pressed against the leg and thus no longer rubs against the bicycle chain , which is usually on the right.
Web links
Commons : Pants clips - album with pictures, videos and audio files