XS Big Dot installed on my Shield. (Took a gunsmith to do it,tight fitting sights.) I like the sights. A problem with 2 holsters. The large sight will hang up on my 12:OO carry TactiPac holster, unless draw is absolutely straight up. Pistol will no longer fit into my cheap Fobus kydex holster. No problems with my N82 fabric holster. Not complaining, just a heads up.