The Lumi Keys keyboard is pretty small, only 24 keys wide, making it great for storing in a desk drawer, shelf, ... meaning the keys are roughly seven-eighths the size of a standard piano key.

A typical piano has 88 keys spanning just over seven octaves. There are other, smaller keyboards or synthesizers that have fewer keys – most come in increments of 25, 32, 49, 61 or 72 keys.