Hillman 3 in. Black & Silver Reflective Mylar Sticker Wide Style Letter B high visibility with its reflective design, making it for a variety of uses. These three-inch letters meet US Coast Guard and 911 requirements for boat registration posting, ensuring compliance and safety. I for use on houses, mailboxes, mailbox posts, jet skis, and boats, this durable sticker combines functionality with ease of application, providing a reliable way to display letters clearly in different environments.