Simplicity 5370; ©1964; Girls' Jiffy One-Piece Dress and Reversible Jacket: Simple-to-Sew. The sleeveless dress has front underarm darts, a high round neckline and a back zipper closing. Pockets are optional. A purchased belt may be worn at the waistline. The reversible jacket, with back waistline darts, is completely lined or faced to the edge. The sleeves are kimono and below the elbow. Detail is top-stitching.