Thinnest IWB? No doubt,it`s gotta be FIST`s ultra thin kydex. A relative carry`s his Kahr K-9 Elite in a FIST ultrathin clip on IWB and it`s awesome. I`ve worn it myself and I actually can`t tell the difference between carrying the gun Mexican style or with the holster. It holds it securely,allows pretty easy reholstering,a fast smooth draw and it adds practically zero bulk to the gun. Also I`m not usually one that cares for clips but the one they use is tenatious,it won`t come loose ven clipped on clothing without a belt. If I couldn`t carry my Keltec with it`s integral belt clip the Kahr/FIST combo would be my next choice. Marcus