Group B nerve fiber
Group B nerve fibers are one of the three classes of nerve fiber as generally classified by Erlanger and Gasser. They are moderately myelinated, which means less myelinated than group A nerve fibers, and more myelinated than group C nerve fibers. They have a medium conduction velocity of 3 to 14 metre [per second |m/s]. They are usually general [visceral afferent fibers] and preganglionic nerve fibers of the autonomic [nervous system]. They are used in Bainbridge reflex as afferents.