content: I didn't know whether to order the 30, 40, or 50 mm but the 40 is perfect, about the size of a golf-ball! maybe a tad smaller.It catches the light so perfectly. I picked up some cheap (clear and thin) fishing line from Walmart, and it looks sublime hanging in my window (all three in a slant)...especially around sunset.You cannot go wrong with this company. I've bought three from them so far, and all have arrived unchipped. Look at the reviews too, they have excellent service, and you can't beat the price!If you love clear or a prism of colors or just beauty in general, these are for you. No reason to hesitate.