Good Ridiculously expensive. These cartridges are the exact same as regular M3 Turbo cartridges, but just a different color. I use a M3 Power (I love the power function because it gets closer with less irritation, even though it's scary at first). However, I use regular M3 Turbo blades because there's no difference and they're a couple of bucks cheaper. I highly recommend the M3 Power razor but not the M3 Power blades.