I believe that's the standard resistance carto, probably around 2.5 OHM's. Some folks like them fine for certain juices, or less
throat hit. The SR will work fine w/ your 900mah, I believe.
If you're struggling with getting of the ciggies tho, the LR at 2.0 OHM might give a more cig-like hit. I don't think I could've got off of cigs if I hadn't used the LR one. It'd be worth it to get a box of each.