Toxonics K953 Metal Fiber Optic Pin Sight. This sight features 3 metal optic pins that are .019, a fluorescent aiming ring, high visibility adjustment scales, a two-inch round composite sight guard. The metal optic pin combines the strength of a steel blade and the brilliance of a fiber optic strand inserted through a channel along its entire length. The half moon shaped steel blade supports the fiber in the event of an impact.