Watch Battery Replacement Gauge. This is a new watch battery replacement gauge. Great for finding the correct battery size for watches, calculators, etc. It measures approximately 8 7/8" x 3 9/16" (225.4 x 90.4 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.