Chris-Wang Portable Pocket Calculator Ruler for Universal 2, 3, 4, 6 and 9 Rings Binder Planner/Notebook/Personal Organizer/Planner Dual power calculator with auto-shut-off With side ruler 8 digital display Size: 8.9x17.2cm, designed for use in Universal 2, 3, 4, 6 and 9 Ring Binders Package included: 1 x Filofax Calculator(Other items are not included)