DB453B Highly durable desk calculator - ideal for regular use. One-touch tax feature and built-in mark up calculator allows you to do complex business calculations with ease. Features and Benefits One touch Programmable TAX feature Large keypad for easy entry Large, 8 digit fixed angle display for optimum viewing Durable hard keys - resistant to wear 3 key memory and +/- change sign key Mark up for gross profit calculations Solar powered with battery backup (Included) Auto power off - saves energy for when you need it mostNotes Dimensions (W x D x H): 102 x 133 x 25mm. Weight: 80g Backup battery ref: LR1130 or BSR54H.