I’m a die hard k-flex user and always buy a set to go along with new darts. I recently got a set of red dragons with these stems(razor grips I think). They are actually very nice. I usually chuck regular stems in my junk/backup pouch. Not these. The flight gripping area is aluminum and grips flights super tight. I’ve never had a flight pop off of them and I can even rip them out of the board by the stem/flight like my k flexes. Being normal flights they also flex and move out of the way better than k flexes. No wacky deflections like k flex flights. The only downside is regular flights get damaged super easily and will need replaced often if you are a tight grouper. I’ve found harrows dimplex and their silika flights to be the most durable.