Calvin Klein lightweight woven Balsa full zip jacket is windproof and folds into a handy small package. Padded Front. Woven material on the front, collar and top of the back has a water-repellent effect. Sides, sleeves and 3/4 of the back are made of knitted stretch material for easy movement. A neat collar has a print on the inside. The round back of this jacket is slightly longer than the front and has two side pockets.