Kilogram

A watt balance which is being used to measure the Planck constant in terms of the international prototype kilogram.[32]
The definition of the kilogram is undergoing a fundamental change—the current definition defines the kilogram as being the mass of the international prototype kilogram which is an artifact, not a constant of nature[33] while the new definition relates it to the equivalent energy of a photon via the Planck constant.

Current definition: The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.

Proposed definition: The kilogram, kg, is the unit of mass; its magnitude is set by fixing the numerical value of the Planck constant to be equal to exactly 6.62606X×10−34 when it is expressed in the unit s−1·m2·kg, which is equal to J·s.
One consequence of this change is that the new definition makes the definition of the kilogram dependent on the definitions of the second and the metre.