When Altberg first began making boots in 1989 they chose the Airgrid moulded original frame, with a covering of Cambrelle®, an ultra breathable material which Altberg also used as a lining in many of its boots. Cambrell® is manufactured in Cumbria in the English Lake District. Altberg continues to use Cambrelle® today in its breathable, non-membrane lined boots, so its been tried and tested for the past 30 years.