If TSD intended to put GL-404 (.394" height) on mine, somebody screwed up. My rear measures .305" above the slide and that includes the space that the over hang is raised above the slide. Even my caliper skills aren't that bad. Regardless, for my purposes they work fine. My primary use is for finding the dot. Good thing, I guess, because Ameriglo also shows GL-404 as discontinued. Wanna kill these ads? We can help!