In an emergency it is vital that rescue crews know your blood type. With a hook and loop strap and a quick release snap hook, these blood type tags can go anywhere you do. Clip them to your pack, vest, jacket or pants. Carry them on or off duty, they just might save your life! Blood type tags come in three colors and 8 blood type options. Measures 4.5" overall. Weighs .28 for 4, mix or match. Sold in 4 pack, your choice. Please specify color.