RedBubble calendars are printed using marvellous futuristic technologies, so complex we can't go into them here, but we can tell you they are lovingly printed on a luscious 200gsm satin art paper at the striking size of A3 (that’s 297x420mm, or 11.69x16.54").
They also have very handy wire binding so you can hang them from things like 'hooks' on exciting places like 'walls'.
You can select your own start month, and order right into the future. Everything about them is brilliant, except you'll have no excuse for missing your sister's birthday anymore.