--Feature: -- Addition and subtraction 2 styles, free to choose. -- Roller design, combined adjustment. -- Add ink, reusable. -- Simply the button to change the question -- Give practice questions efficiently and quickly, without smudging or fading. -- random questions -- Small and exquisite, easy to carry. --Product parameters: -- material: plastic -- Size: 4.4x3x4.8cm -- Printing speed: 2x0.4cm -- Model: Addition (blue) -- Subtraction (pink) --Packing list: 1/2 x Addition and Subtraction Arithmetic Artifact (Includes Ink 5ml)