Portable voice recorders hearing aids electric shavers and heart pacemakers do not need to be shut off at any time during a flight because their signals don 't interfere with aircraft systems .
Reliable market share numbers don 't exist for retro shavers , but not only have gq , esquire , and details featured the products , more than 45,000 members of the online forum badger & blade post daily about shaving with century-old razors .
