Keep a close shave by changing heads every 2 years for the best results Your Philips shaver has a Dual-blade system first blade lifts second blade cuts for a comfortable close shave The Philips shaver has ultra-thin heads with slots to shave long hairs & holes to shave the shortest stubble The skin friendly profile of these Philips shaving heads enables smooth skin contact for a comfortable shave Change heads every 2 years for the best results Super Lift & Cut shaving technology with dual blade system Precision Cutting System Comfort shaving heads