The Gillette Labs blade refill cartridge 4pk can be used with all Gillette Labs razors. Gillette Lab’s razors include the world's first razor with an exfoliating bar, Gillette Labs with Exfoliating Bar, for one stroke exfoliation, and the world's first Heated Razor, for delivering soothing warmth and the feeling of a hot towel barber spa shave. This innovative razor blade refill features five of Gillette’s best blades for a shave that is close and comfortable. The razor blade refill cartridge has an opening in the middle where the heated bar and the exfoliating bar on the razor handle fits and snaps into place with a satisfying “click.” This blade refill cartridge makes it easy to swap in fresh blades, no matter what Gillette Labs razor you prefer to use every day. The Gillette Labs with Exfoliating Bar and Gillette Labs Heated Razor make great gift sets for men, especially when paired with an extra set of blade refills. Feel the difference.