AS AN ATTORNEY I CAN TELL YOU IT IS OK TO USE THE WORD "NON-REFUNDABLE DEPOSIT". SOME LANDLORDS THINK THEY ARE SMART BY CALLING IT A "HOLDING FEE" BUT I HAVE SEEN THAT THROWN OUT OF COURT BECAUISE JUDGES DO NOT LIKE TO SEE LANDLORDS INVENTING NEW TYPES OF "FEES".
Terminology can make a difference ... Depending on the language most commonly used in the rental state, there may be a substantial difference between a holding fee, a rental binder, and a non-refundable deposit. (Consumer laws in some states will not allow for a non-refundable deposits or holding fees beyond a set number of days.)
It is safe to use the rental binder agreement, as it clearly specifies that the monies are non-refundable and that the monies are not a holding fee, rental fee, or security deposit.
Whatever the wording or semantics used, if it is construed by a court to be a rental fee or security deposit it is subject to legal scrutiny and potential for refund.