i am a data engineer so strip 100s of data cables every day, i have had a few different types of cable strippers in the past with different results some of which cut into the cores, this stripper is very fast for stripping data cable and accurate with a screw to adjust the cutting thickness so it is impossible to cut into the cores if the cable is placed into the correct groves, it has 2 groves 1 i use for cat6 and 1 for cat5e
on a couple of occasions i have put the cat6 cable into the cat5e grove and it cut into the cores but this is very rare,
Overall a very good product at a good price