If you have ever done some riding in street shoes then you will know they will soon be marked by the gear shifter when you shift up. Ok not the best footwear for riding however there are times when you are not going to have your boots and riding gear at hand such as travelling light and rent a small bike to explore the area or maybe even just riding short distance at home to shop in afternoon.
I view it as a handy item for travel. If I rent a scooter then no problems but those small wheels really ride poor and forget unsealed roads. If I rent a conventional bike such as the 150cc road trail bikes that are a common in SE Asia then depending on the shifter installed you will permanently mark a pair of walking shoes/sneakers pretty fast. (Some have a two way shifter pedal)
I came across this bit of kit which takes up no space at all but will stop you getting shifter rubber stain marks (or worse) on your shoes. It is made by Rough and Road a large Japanese rider gear brand. It attaches by velcro but what separates this from the many other ones I looked at is the small clip that attaches to your shoe lace and holds the guard in place.(see photo) Without this done up it will soon move and fall off so if you think you could use something like this then get one with the clip. Works fine.
Not exactly a common item but since a few sorts are sold obviously I am not the only one who finds such a thing handy so perhaps this info might be of some interest.