Glowing bright both day and night, tfx sights are always ready.Tfx takes our award-winning tritium + fiber-optic technology even further with all the features our customers requested: compact snag-free design, longer sight radius, and amazingly durable construction built to handle just about anything.Illuminating elements are encased inside a virtually indestructible chemical and shock-resistant capsule and the cnc-machined steel is protected with a rust-resistant fortress finish.Rear Color: GreenType: Tritium/Fiber Optic SetFrame Material: SteelFrame Color: Nitride FortressFirearm Fit: Glock 21Style: 3-Dot High SetFront Material: Tritium/Fiber OpticRear Material: Tritium/Fiber OpticFront Color: Green with White OutlineWindage Adjustment: NoElevation Adjustment: NoFirearm Type: Handgun