I purchased this here before. I inserted a refill once after purchase, but I haven't used it. I have used a few sheets from the included refill. Size: Mini 6 The ring diameter isn't listed, so I'm not sure, but all the refills that came with a 19mm ring binder fit, so I think it's at least 19mm. Color: Apricot I plan to ship via Takkyubin Compact!