Abstract: The present invention provides a cover assembly and pre-filter for use with a high-efficiency particulate filter of a respirator. The semi-rigid cover assembly fits easily and snugly over the high-efficiency particulate filter and remains in place due to friction between the edges of the ribs located on the inside of the cover housing and the sides of the high efficiency particulate filter. In this position, the ribs hold a removable pre-filter against the front face of the high-efficiency particulate filter while the cover housing protects both the pre-filter and high-efficiency particulate filter. This arrangement allows the inexpensive pre-filter which traps large diameter particulate matter, thereby extending the life of the more costly high-efficiency particulate filter, to be frequently and easily replaced.