This lightweight outerwear is perfect for layering and can be worn comfortably from September to May. The buttons have a glossy sheen, like mother-of-pearl. I can't tell if they are made of shell or plastic. I bought this at a department store in 2023 for around 30,000 yen. I haven't worn it much. Navy 417 ÉDIFICE trench coat with side pockets. - Brand: 417 ÉDIFICE - Color: Navy - Style: Trench coat - Buttons: Four-button - Pockets: Side pockets Thank you for looking.