A conventional reel is really a miniature winch which has a spool that holds line. A handle that turns the spool through one or more different gear ratios. The spool is made to turn in one direction. These reels have a form of "Drag" control, which is a device to put pressure on the spool to create resistance against taking the line off the spool, or reversing the spool direction. The size of the spool determines the size of the reel.