I think the cartridge also fuses itself to the blade when it fires, meaning you have to replace that too. There was a collection of blades on the wall that all had the cartridgessandwiches on them. Which is fantastic, all around. That’s what it’s for.

You can remove the cartridge, but it's difficult to assess blade damage. When I set mine off, I said I would reuse the blade. A friend said "you can't see all the damage. If a carbide tooth flies off at speed, your plastic safety goggles won't stop the tooth entering and exiting your skull." Fair!