wall mounted suggestion box is made of premium metal , sturdy and pressure , and not easily deformed . making it waterproof and sun proof , avoiding rust and deform even after long term outdoor exposure with a compact structure that saves counter space . It can be easily installed on walls , doorways , fences , or counters , suitable for locations with limited space . This outside metal Mailbox box features 3 digit combination box , offering up to 1000 possible combinations . Users can customize or change the password at any time along with the included screws and expansion bolts , allow for quick and easy mounting to walls , doors , or fences . No complicated tools are needed , installation can be completed in minutes .