The Centra Rear Sight Anti-Glare Tube is a little shorter and a bit larger in diameter than the Gehmann 559 tube. This Centra Tube is matte finished aluminum, and is finely threaded on the inside to knock down glare. Fits Centra, Warner, PNW, Zelenak, Anschutz and other rear sights. Will not fit RPA sights.
Sinclair, Issue:3A, Page:213