Simple white long-sleeved cut-and-sew, size L. It has a stand-up collar, so the neckline won't stretch out. I think it will be warm in the fall and winter. You can wear it under a sweater or wear it on its own. - Size: L - Color: White - Sleeve Length: Long sleeve Shoulder width: Approximately 47 cm Body width: Approximately 54 cm Length (excluding the stand-up collar width): Approximately 55.5 cm It's made of sturdy and soft fabric. I don't think undergarments will be visible. Thank you for looking.