The belt device comprises a torso portion, a collar portion, sensor elements and at least a first and a second closure element. The first closure element is part of the collar portion on the front side and a second closure element is part of the torso portion on the front side. The closure elements arranged in such a way that they can be opened by a wearer in a comfortable way. The user is able to put on and off the belt system without help of a third person. By the ability to combine different sized collar portions with different sized torso portions a belt device system is provided.