ShurLok SL-600W 4 Dial Numbered Key Storage Combination Lock Box, Blue - 6 Pack Patented dual design provides one combination for the shackle and another for the key door Choose from 10,000 different combinations Durable all metal construction with a hardened steel shackle Easily open in the dark with the ShurLok's zero locking system Store more keys in the ShurLok 2 - front opening style allows 5 house keys