Supplied in refill packs of four six or nine the GilletteLabs universal blade refill cartridge can be used with all GilletteLabs razors including both the GilletteLabs with Exfoliating Bar and the GilletteLabs Heated Razor. The innovative razor blade refill design features four of Gillette’s best blades. What\'s more there is an opening in the middle where the heated bar or the exfoliating bar can simply snap into place with a straightforward \'click\'. The refill cartridges in each pack make it easy to swap in fresh blades regardless of the GilletteLabs razor you happen to be using and make shaving quick easy and overall an enjoyable experience. Furthermore each cartridge refill is designed to offer about 20 comfortable shaves before it will need to be replaced.