Javahed, that rig is dnagerous, plain and simple. Gravity works against keeping it in the holster. There is no retention provided by the flimsy nylon pouch, as there would be with leather, or the firm elastic grip of a unit like the Renegade. You can bet that the 'retention strap' WILL work its way undone, dumping your heater onto the ground.
This says nothing of the totally reversed draw angle. What are you supposed to do, stand deftly on one leg like a flamingo while arcing your ankle up to your gun hand? I can see doing that under any sort of stress. Now, add the weight and bulk of a spare mag into that mess... oh, wait, it will have fallen out of that loop of elastic long before the gun.
Re; Ankle for Mk-9, and Mk-40's. Yes, we do make ankle rigs for both, and also the new Polymer Kahr pistols.
Jim, and Skevlar: Thanks for the compliments my friends.
Lou