Avanti Guardian Key Vault Lock Box - Door Knob Avanti Guardian Key Vault is a durable vault lock box made by Roper. Heavy Pressure Cast Vault Chromate and Baked-On Finish. Combination Lids Changeable 3 Letter Code Easy to Use & Readable Dial. All-Purpose Use Residential, Commercial, Industrial Compatible to Several Types of Interchangeable Lids. The lock box measures 4"x2.5"x1".