Light-density drying swabs, sometimes called “cylinders,” are made of soft, 1–2 lb/ft³ foam. They are primarily used to dry pipelines after most of the water has been removed by a high-sealing pig. They can also be used to gauge pipelines for piggability, absorb and remove fine dust, and perform light cleaning in challenging lines, such as dual-diameter pipelines with size changes too large for standard medium- or heavy-density foam pigs or steel cleaning pigs. Most models are either bare foam (with no coating) or have a polyurethane (PU) coating on one end for additional sealing. This seal helps in lines with lower pressure or flow volume. Fully coated models are also available for longer service life and more aggressive cleaning. Brushes, tracking cavities, and other custom options, including length and outside diameter (OD), can be added. Custom sizes and models are available.