The TRUGLO TFO handgun sights use our patented technology. Unbelievable transition through all light conditions. Glows in the dark. CNC-machined steel construction. Concealed fiber cannot be seen by target. Fits standard holsters. Snag-resistant design. Rear sight available in green or yellow. (Please note that yellow is intended to appear less bright than green.) We recommend that our handgun sights to be installed by a trained gunsmith using a ?sight press?. All other methods of installation will void the warranty..