Hey ! I have a few Klarus flash lights that use the 3V lithion Ion batteries. I was at Radio Shack and they had batteries at 80% off so I grabbed a bunch of what they had left. They are the same size as my Surefire batteries but they are 700mAh 3.7V. Are they safe to use ?

No, not exactly.  3.2v cells would be the equivalent to a CR123A, since they come hot off the charger at around 3.6v, so there's not a huge difference.  If you're using 3.7v labeled cells, they come hot off the charger at 4.20v and if you're running two of them, that's 8.4v freshly charged and will probably blow a driver board meant for ~6v.

Best to just get an 18650 li-ion cell and run it in your Klarus, if it's a 2 cell light.

Chris