uxcell Digits Ultra Thin Pocket Mini Calculator with Key Ring Keychain Clear White LCD display and press keypads make the Digits Calculator easy to use. Color : Clear White, Silver Tone;Size : 3.0" x 1.61" x 0.35"( L*W*H);Key Ring Size : ~0.94" x 0.07" (D*H) This is to protect the, so that they can not contact the battery. This is a nice decoration, you can hang it together with your keys. Give a better gift, let them love to learn.