Talk:Iron Skin/@comment-213.93.125.240-20131015130934

You get a single copy of this mod and every other Rhino exclusive skill mod once you aquire the Rhino Warframe. It doesn't matter if you craft the warframe or buy it from the market (when bought from the market you also get an extra warframe slot and Orokin Reactor with your purchase).

Haven't seen it drop ingame, however i haven't been to the lvl 50+ missions yet, so i assume it's a hard to get uncommon. Luckily, warframe skill mods tend to fuse cheaper than normal mods so there is no reason to hunt for one if you already have your Rhino warframe and initial Iron Skin mod. Got mine maxed with just a few uncommon 5 ones.

One sidenote: You can't recast Iron Skin if you still have some left from a previous one. This can be annoying in No Shield or Energy Drain Nightmare missions as you want to have it up asap before you loose precious health and/or energy.