Interestingly, "liter" is a customary metric unit, but not an SI unit. SI requires you to use units of length-cubed for volume. In this respect (partial antiq

Interestingly, "liter" is a customary metric unit, but not an SI unit. SI requires you to use units of length-cubed for volume. In this respect (partial antiquation in the wake of unit redefinitions) liters have something in common with the quart.