The following Mitutoyo model has an extra thin blade thickness of .016", and blade length .118"
The following Mitutoyo model has carbide blades with blade thickness .016", and blade length .157"
A note about carbide blades: although they won't wear down like steel blades, thin carbide blades are brittle and sooner or later they will break off, usually when you inadvertently "twist" the micrometer while it's in a groove, and usually while you're in the middle of an important project. Repairs are possible but quite expensive when the carbide needs to be replaced. The moral: don't buy carbide unless you have a good reason.