Look's S-Track Cleats are for use with Look's S-Track pedals. The cleats come with three sets of shims of varying height. You can tune the height of the cleat to dial in your shoe-to-pedal contact area. It'll improve your overall comfort and efficiency. The S-Tracks have 3 degrees of float and a 15-degree release angle.
Look's S-Track pedals use elastomer pads on the cleats to deliver massive surface area. The pedal is in contact with the cleat (light green) and your shoe's lugs (blue) for better contact and improved comfort. More contact = better efficiency.