Haven't tried the Klein. Don't recall the brand of my automatic strippers off hand.
Due to the small size of the individual conductors in the speaker wire, my automatic strippers did a poor job. Sometimes not stripping ant all and other times cutting some of the strands. A pair of manual strippers for the small gauge wire worked better but still had some issues. Plus they were very tedious to use.
What I have found to work best is a PATCO thermal wire stripper
https://patcoinc.net/ . They offer fixed and variable temperature strippers depending on your need. The low temp units heat up to 450 degrees F while the high temp units heat to 1,500 deg F. The low temp units should work on the speaker cables. I haven't tried them though because I have a high temp unit.