Well, 26RM is not neccessarily safety chain...26RM2 is. It is identified for sure by the triple humped tie straps which reduce kickback. Stihl suggests eevryone use low kickback chain, but once you've had the pro stuff, it's hard to go back, cause it sucks to cut with the low kick chain IMO. The difference between RM and RS is that the RS has chisel cutters...whereas the RM and RM2 have chipper or semi chisel cutters. Do you have any serious experiecne running a saw? If not go with teh safety chain...if you do, go with the 26RS.....all will be well if you use good sense and watch out espeically if you plunge cut and don't let the bar nose hit anything when youa re in a cut...it's that nose area of teh bar that is kickback prone.