(1) A revocable trust instrument may refer to a written statement or list to dispose of items of tangible personal property not otherwise specifically disposed of by the trust, other than money.
(2) To be admissible under this section as evidence of the intended disposition, the writing must be signed by the settlor and must describe the items and the devisees with reasonable certainty.
(3) The writing may be:
(a) referred to as one to be in existence at the time of the settlor's death;
(b) prepared before or after the execution of the trust;
(c) altered by the settlor after its preparation; and
(d) a writing that has no significance apart from its effect upon the dispositions made by the trust.