The technical differences between the Braun Series 9 Pro+ models such as 9597, 9590 and 9577 are mainly to be found in the colours and the accessories supplied. There are no significant technical differences in shaving characteristics or performance. All models offer wet and dry shaving, have five cutting elements and a battery life of 60 minutes. The main differences lie in the colour options and the accessories supplied, such as travel cases or PowerCases.