  We present qualitative pictures of the structures of magnetic monopoles
(MMs), nuclearites (nuggets of strange quark matter, strangelets, surrounded by
electrons) and Q-balls (supersymmetric states of squarks, sleptons and Higgs
fields). In particular we discuss the relation between their mass and size.
MMs, nuclearites and Q-balls could be part of the cold Dark Matter (DM); we
consider astrophysical limits on the flux of these particles in the cosmic
radiation.
