Attention! Shipping costs paid by Boldking only within Europe! Recycling envelope. For 12 used blades. No postage stamp required. Boldking is the only shaving brand to offer a recycling program. Used blades can be returned in the cartridge in the Recycling Envelope. This includes 3 cartridges (so 12 blades total). All you have to do is put them in the mail (without a stamp) and we recycle the material to make it something new!