GILLETTE MACH3 TURBO BLADE X4 is a good blade containing four refills and three compatible razor blades head that has a lubrication strip, Microfin Comfort Skin Guard™, and DuraComfort™. To Use: Cleanse the face and apply your preferred shaving foam. Check if you have to switch to a brand new blade (Do so when the lubrastrip fades to white or each razor stroke feels duller than usual). Press the button at the back of the cartridge for a smooth release. Then, slide the handle into the replacement cartridge and wait for a clicking sound. Now shave, wash and rinse the blade carefully.