The FEATHER FHS Single Edge Blades are the only blades that will work in a OneBlade razor. Made in Japan from hi-stainless carbon steel with a platinum & PTFE coating, these blades are ultra-sharp yet comfortable. At 0.23mm thickness, they are twice as thick as the average double edge blade. If you shave 5-7 times per week, 90 blades should last you about 6 months.