Universe-in-a-Box 22-piece Set neutron This is a made-to-order

This is a made-to-order

Also part of the Antiparticle 14-pack

Of course you won't get the full effect of their varying weightiness

and Electron-neutrino

Approximately 15 oz (425 gm)

Universe-in-a-Box 22-piece Set neutron This is a made-to-orderThe UNIVERSE IN A BOX 22 PIECE SET contains all the particles from the Standard Model plus four Theoreticals and Two nucleons, for a total of 22 particles, covering most of the known universe. These miniature particles are replicas of the regular particle plushies but are about one third the size. They fit neatly in a reuseable, sturdy, black cardboard box and the set includes a 24 page mini booklet explaining each particles properties, stats and fun