Oecobius navus

These are the tiniest fully grown spiders I encounter. Body length just 3 mm.
This is a cribellate spider - the cribellum is a silk spinning organ. Unlike the usual spinnerets of spiders, the cribellum consists of one or more plates covered in thousands of tiny spigots, tiny holes that hardly project from the surface, in contrast to the elongated spigots that project from spinnerets.