Vault Locks Prudential Lockbox Model 5000. 4-digit Numeric Lockbox Sturdy Vault Locks construction prominently displaying the Prudential Real Estate logo. Same design and function as other Vault Locks lockboxes with a large body; able to hold multiple keys and/or key cards. Door Guard rubber bumper protects surfaces. Black. 4-digit numeric combination preset to 0-0-0-0. Set your own combination.