TruGlo's TFO fiber optic handgun sights has unmatched visibility in all shooting conditions. It utilizes quality Swiss tritium for maximum brightness and has a Fortress finish that provides a permanent protective coating for maximum protection. This model is compatible with Glock 17,17L,19,22,23 ,24,26,27,33,34,35,38,39,45 and has yellow rear sight. Product Features nitride Fortress Finish Duty Proven CNC-Machined 24/7 Brightness Assembled in the USA DISCLAIMER: GLOCK is a federally registered trademark of GLOCK, Inc. and is one of many trademarks owned by GLOCK, Inc. or GLOCK Ges.mbH. Neither Sportsmans Outdoor Superstore nor this site are affiliated in any manner with, or otherwise endorsed by, GLOCK, Inc. or GLOCK Ges.mbH. The use of GLOCK on this page is merely to advertise the sale of GLOCK pistols, parts, or components. For genuine GLOCK, Inc. and GLOCK Ges.mbH products and parts visit www.glock.com.