The trouser zipper (concealed on one side) is closed from the left to the right on ladies' trousers and from the right to the left on men's trousers. Use a zipper 1"-2" (2.5-5 cm) longer than required finished length. Ladies' trousers: Finish the raw edges of the seam allowance and extension. Sew the front crotch seam, ending 1 cm (3/8") before the fabric extension. Fold the left front seam allowance under along the centre foldline. Press. Press under the right front seam allowance approx. 7 mm (1/4"). The allowance edges will overlap. Attach Zipper foot 4. Place the zipper to the back side of the underlap with the teeth close to the folded edge and the zipper pull extending beyond the top edge of the garment. Move the needle position to stitch close to the edge of the underlap. Position the left front over the zipper and pin the fabric layers together aligning the centre line of the underlap and overlap. Turn the trousers over and pin the zipper tape in place on the fabric extension, making sure not to pin through the front fabric layer. Fold back the extension and stitch close to the edge of the zipper teeth, making sure not to catch the front fabric layer in the seam. Fold the extension back in place. From the right side of the fabric, topstitch the left extension approx. 3 cm (1 1/4") from the centre seamline. Gently curve or angle the stitching around the bottom end of the zipper. We recommend using the edge guide for topstitching. For men's trousers follow the same procedure having the underlap on the left and the overlap on the right.