which can determine both the width and length size values of the foot. A metric standard for shoe sizing, the Mondopoint system, was introduced in the 1970s by International Standard ISO 2816:1973 "Fundamental characteristics of a system of shoe sizing to be known as Mondopoint" and ISO 3355:1975 "Shoe sizes – System of length grading (for use in the Mondopoint system)". the current version of the standard is ISO 9407:2019, "Shoe sizes—Mondopoint system of sizing and marking". The Mondopoint system includes measurements of both length and width of the foot. Accessories Foam tap: a small foam pad placed under the ball of the foot to push the foot up and back if the shoe is too loose. Heel grip: used to prevent the shoe from slipping on the heel if the fit is not perfect Overshoes or galoshes: a rubber covering placed over shoes for rain and snow protection. Shoe bag: a bag that protects shoes against damage when they are not being worn. Shoe brush and polishing cloth: used to apply polish to shoes. Shoe insert, insole or inner sole: orthopedic or regular insert of various materials for cushioning, improved fit, reduced abrasion or to keep shoe fresh and increase its durability. These include padding and inner linings. Inserts may also be used to correct foot problems. Shoe polish: a waxy material spread on shoes to improve appearance and glossiness, and provide protection. Shoe stretcher: a tool for making a shoe longer or wider or for reducing discomfort in areas of a shoe. Shoe tree: placed inside the shoe when user is not wearing it, to help maintain the shoe's shape. Shoehorn: can be used to insert a foot into a shoe by keeping the shoe open and providing a smooth surface for the foot to slide upon. Shoelaces: a system used to secure shoes. Snow shoe: a wooden or leather piece that increases the area of ground covered by the shoe. Removal of shoes In many places in the world shoes are removed when moving from exteriors to interiors, particularly in homes and religious buildings. In many Asian countries, outdoor shoes are exchanged for indoor shoes or slippers. Some fitness centres require that shoes be exchanged for indoor shoes to prevent dirt and grime from being transferred to the equipment. See also Foot binding List of shoe companies List of shoe styles Locomotor effects of shoes Runner's toe,