I bought 50 Gille tte Sensor Excel Razor Blades off of ebay from a seller that goes by wsader. They were packaged in authentic looking packages. They shaved like a hastily sharpened steak knife and under a microscope looked like it. He refunded my money. This is from his original ad.
Gillette Sensor Excel Razor Blades - 50 Cartridges

Item specifics
Model: Gillette Sensor Excel Brand: Gillette
Modified Item: No Non-Domestic Product: No
Country/Region of Manufacture: Germany Type: Cartridge B