Lever harps generally range from 22 to 36 strings. They can be acoustic or electric. The levers allow the player to switch from one key to another and to play some accidentals. Lever harps (aka folk harps) weigh less than pedal harps and don't require the maintenance that a more complex pedal arrangement does. Because notes are changed one at a time, it can actually be easier to deal with some accidentals. If you have a g# in one octave and g naturals in every other octave, you just set it at the beginning. With a pedal harp, you would have to switch the pedal back and forth, since one pedal controls all the g strings.