Thanks so much, you are one of a kind and obviously concerned about your business and the people who buy from you! Most businesses really don't care what their customers want, just "take what we have" and that's that. Thank you again.
Size is as-packaged, or the diameter of loose marbles. ("D" is the diameter of round items other than marbles.)
This tube of glow-in-the-dark 5/8" marbles makes a wonderful night-light! The Marbles need to be "charged" before they will glow - shine light on them (or hold them close to a light bulb) then when you turn off the lights they will glow like crazy! Kids will love to charge them before packing them back up and taking them to bed.