one shot one fit / key

Not knowing the right direction to insert the key, many people usually try fitting it into the hole several times. One Shot One Fit shows the right direction to insert the key into the matching hole, using color and touch. Because the color-engraved parts stick out, they intuitively tell you the right direction as you touch them. It is useful when it’s dark and therefore difficult to perceive the proper color. It is helpful for visually challenged people as well.