CA Prob Code Section 3903

(a)

A person having the right to designate the recipient of property transferable upon the occurrence of a future event may revocably nominate a custodian to receive the property for a minor beneficiary upon the occurrence of the event by naming the custodian followed in substance by the words:

“as custodian for (Name of Minor)

(b)

A custodian nominated under this section must be a person to whom a transfer of property of that kind may be made under subdivision (a) of Section 3909.

(c)

The nomination of a custodian under this section does not create custodial property until the nominating instrument becomes irrevocable or a transfer to the nominated custodian is completed under Section 3909. Unless the nomination of a custodian has been revoked, upon the occurrence of the future event, the custodianship becomes effective, and the custodian shall enforce a transfer of the custodial property pursuant to Section 3909.