The Particle Zoo stampsheet (series 4 design)
One high-quality 8.5x11 inkjet print. It's a perforated sheet of "stamps" featuring 23 of the particles (please note stampsheet is not gummed ).
$5 + shipping

(If you are interested in purchasing series 1, 2 or 3 stampsheets from earlier this year, there are limited quantities available. Please inquire: particle @ particlezoo.net).