2 Chime Clock Keys. This is a new set of two chime clock keys. You receive: One size 6 with a hole size of 3.75 mm. One size 8 with hole size of 4.25 mm. 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.