3 Single End Clock Keys. This is a new set of 3 size 8 single end clock keys. These are used for winding clock mainsprings. Each has a 4.25 mm hole. You receive: One size 8 grandfather clock crank key. One size 8 brass clock key. One size 8 nickel plated clock key. We work hard to update our descriptions and pictures of our merchandise. As part of a process of ongoing innovation by our suppliers, newer versions of the item shown may be shipped before we are able to complete an update. As a result there may be a slight variation in color and design.