Textile BK 1 trousers featuring detachable thermal lining and membrane. Because we understand the everyday needs of a biker who has to be resistant to wind, rain and the dangers of a city, we have developed the BK 1 textile trousers. Their detachable membrane and thermal lining make them a perfect everyday companion. Riding or roaming around, the loose fit and flexible panels above the knees won’t be restricting your movement in any way.