10 - 24x24 Micropower Guard replacement compatible filters NOTE: White or Blue or Yellow coloring of pads is simply different dye colors. There is no difference in performance or quality. DO NOT MEASURE THE FILTER MEDIA ITSELF. There is a label right on the black plastic part at the top near where the power supply plugs in. Can't find it? Look inside the track of the black plastic part. This label gives the dimensions to order by. Can't find a label? Measure the entire air cleaner end-to-end and top-to-bottom including the entire frame and black plastic part at the top. DO NOT MEASURE THE FILTER PAD ITSELF. Replacement Media Pads Only , NO FRAME INCLUDED . These replacement pads utilize a full sheet of activated carbon between two outer fiberglass layers. To install, simply lay the replacement pad on-top of the electrode and close the filter frame. When the filter frame closes the electrode will puncture the first layer of fiberglass to contact the full sheet activated carbon. This contact will allow the voltage to be transferred from the electrode to the replacement pad.