Head restraint system

The present disclosure relates to an inflatable head restraint system (3, 3') comprising - an inflatable airbag (23, 23'), and - a housing (5) for storing the airbag (23, 23') in a packed condition, The housing (5) is adapted to be located behind the back of a head (21) and/or a nape (30) of a user of the inflatable head restraint system (3, 3'), and the airbag (23, 23') comprises a portion (27, 37) adapted to at least partly enclose the head, when the airbag (23, 23') is in an inflated state, thereby restraining movement of the head (21) in a direction away from the housing (5). The disclosure further relates to a vehicle seat (1, 15, 15', 15") comprising such an inflatable head restraint system (3, 3'), a kit comprising the inflatable head restraint system (3, 3') and a transmitter (49), a vehicle (45) as well as a method for activating inflation of the airbag of the inflatable head restraint system.