The PT18 is the largest flashlight out of the PT series but it's still incredibly compact, barely under 4 inches in length. The PT18 fits comfortably in your hand and has an easy-to-access side switch that allows you to turn ON and OFF the flashlight and cycle through modes. The shape of the flashlight can be a little awkward because the head is a bit larger than the rest of the body. The PT18 is truly a fantastic light!