Hillman 3 In. Black & Silver Mylar - Wide Style - Reflective - M features reflective letters that are three inches and larger, designed to meet US Coast Guard and 911 requirements for boat registration posting. These versatile letters can be used on houses, mailboxes, mailbox posts, jet skis, and boats, providing clear and durable identification. The black and silver mylar material ensures high visibility and a wide style for easy readability in various lighting conditions. This product is i for anyone needing compliant and reliable reflective lettering for outdoor use.