· World's # 1 Foil Shaver Brand· Official Electric Shaver of the NFL. For Series 3 new generation cruzer Clean Shave· Shaver head should be replaced every eighteen months.· Replacing your razor head gives a 25% better shave. For optimum performance; clean regularly.· The replacement head get's your shaver back to 100% performance and a closer shave.· Fits the following braun shavers model no. series 3 ranges (340, 370, 390)· Blades should be replaced every eighteen months· For optimum performance, clean regularly