Didriksons Mens Calvus Pants 2Didriksons Mens Calvus Pants 2 Calvus is a technical 2 layer pant, 100% waterproof in both material and construction. The fit is ergonomically cut for maximum freedom of movement. The pants are reinforced with a stronger fabric at the knees, at the ankles and at the back. The waist is raised at the back for extra protection regardless of body position. To adjust the waist width, there is a built in belt with buckle at the front. The fly can be opened