Second what SD recommended. A PLHv2 in 18650 body length fits awesome on your IWC mount with a 14" barrel. If you're running the factory handguards, the tailcap suggestion is best. If you're running a SF M80 or Agency handguard, then you have some remote switch options i.e. Hot Button, Modbutton Lite, ect. Here's mine with a SF Scout and Modbutton Lite on an M80 rail.