An intermediate lock mechanism is formed by first and second lock pins, an advancement restricting groove, and a retardation restricting groove. 04% to about 95% molar fraction of said mixture of oxygen and carbon dioxide. The filters have Teflon coated, stainless steel mesh, which is housed in plastic skeletal structures. Upon being driven by the driving units, the protective cap units are pivotally rotated in relation to the fixing base between a protective shielding position and an open position in a synchronous manner. The personal defense device may optionally include a one or more cameras and a wireless communication link for transmitting status information, images and audio to a monitoring station. The training device further comprises a converter means controlled by the microprocessor and connected to the sound playback means for converting the detected values of the said parameters into verbal training information for the training person and outputting them by the sound playback means.