An exhaust system of a diesel engine has a diesel particulate filter for treating exhaust gas. It includes an illumination filmstrip, a grating plate, a transparent back plate, two step motors for driving the grating plate to move up and down, two sensors and a set of sensing elements, and a one-chip microcomputer. In addition, the user interface may provide a list of the members of the designated group, with icons indicating the current status of the group members. The two electrodes may include an attachment operable to releasably connect the two electrodes to the patient. Alternatively, a design choice can be made to achieve a combination of improved performance and reduced size, depending on the application. When the strap device 15 is used for a shoulder strap for a bag which has a good appearance.