The String Set, or String Instrument Set, is a collection of three orchestral string instruments in the Animal Crossing series that first appeared in Doubutsu no Mori. To play the instrument, the player can press A near it while displayed in their home or tap it with the stylus.
Doubutsu no Mori, Doubutsu no Mori+, Animal Crossing, and Doubutsu no Mori e+
Animal Crossing: Wild World
Animal Crossing: City Folk
Animal Crossing: New Leaf