A respirator 10 that includes a mask body 14, a filter cartridge receptacle 15, and a filter cartridge 12. The filter cartridge 12 has a side 30 that is capable of being plugged into the receptacle 15. The filter cartridge 15 can be inserted into the proper position within the receptacle 15 while the mask body 14 is being donned. The securement can be achieved without having the user visibly witness the actual engagement. An audible click or other indication can be provided so that the user knows that proper engagement has been achieved. The engagement may exhibit little spacing between the filter cartridge 12 and the mask body 14, thereby improving viewer visibility and making the inventive respirator 10 more comfortable to wear.