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Yeah, measuring an octo is nearly impossible but when she's inflated, her mantle is about the size of a big lemon but can stretch to 5+ inches when she does the pointy mantle thing. I've seen her arms stretch to about 14 inches or so. If it helps, the tube she is holding on to is about 1/2 inch in dia. I'll try to get some size comparison pics sometime soon. Thanks for the comments, John