This is a filter for Drive Medical's Power Neb II piston pump compressor. The Power Neb II has 2 different models, each using a different type of filter. To determine which filter you require for your Power Neb II, look for the serial number on the compressor. If the serial number begins with "2M" then you require the Square Filter. If the serial number on the compressor begins with "1E" then you need the round filter. Be sure to select the correct option from the drop down menu above before ordering your replacement filter.
Filters should be replaced every 30 days or sooner if they appear dirty. The square filter is sold individually while the round filter is sold in a pack of 10.