Size 12 x 12 x 18.5": (HxWxD) locking mailbox holds 2-3 days of mail. Easily accessed by mail carriers and delivery drivers, our post mount mailboxes for outside receive small and large envelopes, poly-bag style mailers and packages up to 16 x 10 x 2 . Receive What You Buy: Prevent identity, mail and package theft. Stop porch pirates with our locking mail boxes for house outside. This post mounted mailbox features an anti-phishing panel and anti-pry latch. Keep out sticky fingers with Adoorn s mail box.