Changing lenses on your camera when you are in the field can cause dust and debris to land on your sensor when it is exposed. The 100-pack of Type 2 Sensor Swab Ultra from Photographic Solutions is a 17mm wide swab designed to clean oil, dust, and debris from a digital camera's CCD or CMOS sensor.
The thick and double wrapped swab is highly absorbent, and each swab is individually packaged to maintain the purity of the swab for cleaning. Additionally, fibers from the Sensor Swab do not shed once the sensor has been swiped across. Furthermore, Photographic Solutions recommends not removing the Sensor Swab from the wrapper until you are ready to use it, since debris may catch onto the swab and transfer to the sensor when cleaning.