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 12-pack of Type 1 Sensor Swab Ultra from Photographic Solutions is a 20mm 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.
Canon: EOS-1D, EOS-1D Mark II, EOS-1D Mark II N, EOS-1D Mark III, and EOS-1D Mark IV
Fujifilm: Finepix S1, S2, S3, and S5 Pro
Kodak: DCS620, DCS620X, and DCS760
Nikon: D300, D300s, D2X, D2Xs
Pentax: K-5 II and K-5 IIs
Sigma: SD9 and SD10