The Hopkings Towing Solutions 2 Pack Oblong Stick-On Reflectors Red B278SRW are easy to install and ideal for any safety application. The reflectors can be used on trailers and trucks school buses agricultural equipment and more. Acrylic lens is tough and durable and reflects well day or night. Surface mount using the adhesive backing or on 3-15/16 centers with two screws (screws not included). Easy installation and stays in place in adverse weather conditions. Each reflector measures 4-3/8 x 1-3/8 .