They are 20mm by 20mm, and weigh about 13g per bead, making them slightly larger, and considerably lighter than the titanium version.
Because aluminum is a much softer metal than Ti, the surface of these will get dinged and scratched, and over time, the anodization will wear away, and the raw aluminum will show through (see blue/ red photo as an example). This aging process gives them a great texture which helps with grip and bead control, and eliminates the need for machined knurling.
They come with several extra strings, a fist full of stickers, a canvas carry bag, an info card, and a slick little gift box. ( Natural version comes in a drawstring bag)