Work trousers with knee zipper This easy to maintain, durable work trouser 2 in 1 is made of polyester and available in various colors. The robust materials and many practical pockets make the pants great for work, leisure and professional use. This classic ARMY pants is comfortable, easy to clean and is practically indestructible. It is one of our most popular products. The work trouser is made of 65% polyester and 35% cotton.