5 Meters (16ft aprox) of foam underlay with granite ballast bonded to the foam. Very flexible and easy to work with thanks to sleeper indentations. The track just falls into place and gets pinned down using longer pins like the GM67. For additional effect you can use the corresopnding loose ballast to fill in any areas which require more ballast such as yards or stations.

CLICK HERE to view an article on how to use Gaugemaster Ballasted Underlay.