DE cartridge razor: Evoshave

I notice that they claim that an 8-pack of their DE blades will last more than 4 months.

4 months = 120 days. 120days / 8 blades = 15 days.

What the heck are they making these things out of?
You're assuming daily shaves.
15 days, one shave every 5 days.... 3 shaves per blade. See?
The blades are made from pure marketing blurb of course. Lasts forever...